How many types of gems are there. Types, names and colors of gemstones for jewelry and jewelry: a list, a brief description with photos. How to distinguish a natural real stone from a fake, from glass in jewelry

The radiance of sapphires and agates beckons you with its brilliance, and the mysterious onyxes and aquamarines, fraught with magical power, invite you to learn everything about them... Here you can see the true charm of stones, choose the right one according to your horoscope, magical power and beauty.

Stones, small or large, colored or transparent, precious and semi-precious, have always attracted people. From the most ancient times, it was customary for almost all peoples, even in ancient Egypt and the wild tribes of Indians in America, to decorate clothes, hair and dwellings with beautiful stones. After all, people believed that a stone, as one of the five elements of power, harbors a soul. It has its own strength, natural energy.

A scattering of shining stars

Such beautiful and such different semi-precious stones! The list and description of them can take many pages. We will tell in this article about the best and most common. You will find out which stones are most suitable for health, in the form of amulets or simply as beautiful accessories. And also we will present you a list of semi-precious stones in alphabetical order.

ABC of stones

List of precious and semi-precious stones in alphabetical order:

• aventurine, azurite, aquamarine, amethyst;
• turquoise, beryl;
• vesuvian, variscid;
• jet, rock crystal, garnet;
• jade, pearl, jade;
• serpentine, zonochlorite;
• quartz, corundum, cat's eye;
• lapis lazuli;
• malachite, macaite;
• jade, nepheline;
• obsidian, opal, onyx;
• rhodonite, rauchtopaz;
• sardonyx, carnelian;
• topaz, tiger's eye, tourmaline;
• chalcedony, chrysoberyl, chrysolite;
• citrine, zircon;
• amber, jasper.

A little about astrology

When choosing the right stone, it is very important to consider its energy comparability with your horoscope. Some of them are suitable only for certain signs of the zodiac, while others can be harmful with their unwholesome influence, enhancing the negative traits of their character. It is also important to consider which element you belong to.

Precious and semi-precious stones. Liststones,suitable for the sign of the zodiac

	Diamond, cubic zirconia, citrine, sapphire
	Agate, turquoise, emerald
Twins	Beryl, alexandrite, topaz, heliodor
	Pearl, moonstone, chrysoberyl
	Amber, topaz, chrysolite, sapphire
	Malachite, aventurine, carnelian, pomegranate
	Tourmaline, diamond, amethyst, opal
Scorpion	Garnet, aquamarine, alexandrite, beryl
	Chalcedony, onyx, pyrite, yellow topaz
	Serpentine, tiger eye, obsidian, sardonyx
	Amethyst, zircon, jasper, tourmaline
	Mother of pearl, aquamarine, pearls, chrysoprase

healing power

Each stone is not only a beautiful decoration, it also affects the fate of its owner, and can also have a beneficial effect on his physical health. We present you a list of semi-precious stones capable of healing.

1. Jet. Smooth with a bright sheen. It is a type of coal. According to one of the legends, it belonged to the goddess of the earth - the Great Mother. Considered a stone of fertility and feminine energy. Helps with gynecological diseases and infertility. Makes childbirth easier.
2. Aventurine. It has a golden sheen and a smooth matte surface, it can be of different colors. In this case, yellow and green are most common. It enjoys special honor in China, where it is called the imperial stone. Protects from the evil eye and attracts wealth. It has a good effect on development and growth, so it is ideal for children.
3. Rhinestone. Like petrified, frozen ice, this stone is striking in its purity. Formed in the form of crystals on mountain peaks. The peoples of Tibet used the stone to heal wounds and abrasions. It is believed that gives the owner the gift of clairvoyance. Especially revered in China and Tibet. Strengthens is used during meditation, as a guide to the world of the dead.
4. Jasper. It has a smooth matte surface with a golden sheen. May be different colors. It has a beneficial effect on brain activity, improves memory, and relieves headaches. It helps with important meetings, calms and increases concentration. Speed ​​up the healing of injuries
5. Pomegranate. Usually red in color, translucent, similar to pomegranate seeds, which is why it got its name. But other colors may also be available. Improves the work of the cardiovascular system, lungs. It is a talisman of love. He is often given to his soulmate, it is believed that he holds hearts together forever. It is also recommended for creative people. Helps with the work of artists, writers, musicians.

Amulets and amulets

Since ancient times, people who bore the title of sorcerers, magicians, shamans, druids and even alchemists have used the unusual, magical power of stones. They hung themselves to protect themselves from evil spells. Also used in rituals and semi-precious stones. The list of their magical properties was huge. Starting from protection and healing, ending with damage and curses.

List of semi-precious stones with magical properties. The best gemstones

1. Aquamarine. Transparent and similar to blue ice, this crystal stone has always been considered the patron of the deep sea. It was worn by sailors as a talisman. Able to change color in response to human energy. It was believed that it saves from poisoning and attempt on life, protecting its owner. It also tends to establish conflict situations, it can be seen on people involved in judicial issues and jurisprudence. Crystal stone of truth and purity.
2. Beryl. A transparent stone of light green color, but varieties of other shades can also be found. Due to its strong energy, it was used as a basis for the manufacture of magical devices and church utensils. It is considered the best stone as a talisman or as a magical talisman. Helps improve metabolism and strengthen immunity.
3. Hematite. It has unique chemical properties. Due to the fact that during processing it colors the water scarlet, it has received the nickname bloodstone. It is considered a source of power, in connection with which it is actively used by magicians and sorcerers in rituals. Usually has a black and metallic color. Often worn by kings as a talisman against dark forces. It is best to set it in silver. It is believed that it helps with any diseases of the internal organs. Improves blood circulation and heals cardiovascular diseases

About the use of stone talismans

Many people believe that the talisman brings them good luck. Accompanies a favorable outcome in business. It can be a talisman for love that you give to your loved one, thus binding your souls; can be a talisman for wealth, bringing good luck in transactions and increasing the chance of winning the lottery. In any case, in the form of a talisman it is difficult to pick up a thing better than a stone. In order for it to bring you happiness, you need to choose it correctly. It is best to do this in accordance with the astrological horoscope. After the acquisition, you need to wash off someone else's energy from the stone, leaving it overnight in holy water. In the morning, do not forget to meditate, charging the stone with your energy.

Beauty is more precious than gold

Indeed, many people prefer ordinary beads and bracelets made of semi-precious stones to gold jewelry. It looks so amazing that it can completely overshadow the brilliance of gold and diamonds.

The most beautiful semi-precious stones (list with photo). Top 5

All the colors of the rainbow

What is your favorite color? Choose your jewelry to match the color of the outfit! We present you precious and semi-precious stones, the list of which is sorted by color.

Here they are different - opals, rubies and onyxes. But whichever you choose, remember: all semi-precious stones have power. The list and name of each, as well as a description of their properties, you can find in special books on gemology - the science of studying precious and semiprecious stones.

Stones are natural and synthetic. Natural stones can be of mineral or organic origin.

In jewelry practice and in trade, stones are classified into precious, semi-precious and ornamental.

To precious stones include stones of mineral origin - very hard, transparent: diamonds, emeralds, rubies, sapphires; organic origin - pearls.

For precious stones, the weight unit is a carat, equal to 0.2 g, and for all other stones, a gram.

Diamond- hardest stone a cut diamond is called a "brilliant". Depending on the number of defects, diamonds are divided into 8 groups, the most valuable "pure water" diamonds.

emerald(from the Greek "smaragdos" - hard) - a fragile stone of a grassy green color.

Ruby(from the Latin "rubech" - red) is a variety of red corundum mineral.

Sapphire(from the Greek "sapphieros" - blue) - a transparent variety of corundum of various colors - from dark blue to pale blue. Natural sapphire is considered a rare stone, although it is valued cheaper than ruby.

Pearl- a precious stone of organic origin, formed in the shells of sea and river mollusks. The color of pearls is from white to black. The larger the pearl grain, the higher its value.

Semiprecious stones. Semi-precious stones are transparent, colorless or colored stones. The unit of mass of semi-precious stones is the gram. Semi-precious stones include:

siaexandrite- under different lighting changes color from thick green to raspberry red;

chrysolite - transparent mineral from yellowish green to deep green, the stone is quite rare;

turquoise(from Persian, "firuza" - a stone of happiness) - an opaque mineral of sky-blue color, goes well with silver;

pomegranate- solid, can be transparent, translucent and opaque, reddish shades (more than 30). Pomegranate is used both as a base and as inserts for jewelry (bracelets, beads, necklaces, etc.);

topaz- the stone is heavy, hard, transparent, mostly yellowish, but there are also other shades.

Semi-precious stones also include spinel, amethyst, aquamarine, beryl, tourmaline, zircon, hyacinth, opal, moonstone, rock crystal, smoky quartz and stones of organic origin - amber, coral.

Amber is a fossil resin of coniferous trees of the Tertiary period. Transparent amber with inclusions of insects and plant particles is valued. Amber is used for making beads, brooches, earrings, bracelets, etc.

Coral is a calcareous mass of skeletons of invertebrate marine animals. Coral comes in pink-white, white and reddish shades. Coral is a valuable material for making earrings, necklaces, beads, and jewelry inserts.

Ornamental stones. Ornamental stones are opaque minerals or slightly translucent, inferior in hardness to semi-precious stones. Ornamental stones have beautiful patterns and colors, so they are widely used in the jewelry industry.

Chalcedony- hard ornamental stone, grayish-blue color. There are many varieties of chalcedony.

Carnelian - a variety of reddish chalcedony (quartz group).

Agate- is of volcanic origin, is a multi-colored-patterned variety of chalcedony.

Onyx - a variety of multi-colored agate, used by the ancient Greeks and Romans for carving cameos and amulets.

cat eye - a variety of agate of different shades; the stone, polished as a cabochon, gives an ebb and play, reminiscent of a cat's eye, when moving.

Jasper it can be of a very diverse color of various shades, more often it is painted in a brick red or brown color. Jasper is used as a facing, decorative material for columns, lamps, etc.

Malachite- an opaque mineral containing up to 57% copper, has a green color of different shades. Malachite is a stone of medium hardness, in the cut it has a complex beautiful pattern.

In the manufacture of jewelry, artificial stones are used - crystals. Some of them are called synthetic.

Synthetic emerald has the characteristic features of a natural gem.

cubic zirconia - got its name from the first four initial letters of the name of the institute where it was created (Physical Institute of the USSR Academy of Sciences). The starting material for finite is mainly zirconium and hafnium oxide.

In the production of jewelry, various decorative and ornamental materials are used: glass, bone, horn, papier-mâché, plastics, etc.

General classification of jewelry stones

For natural jewelry stones, there are many different classifications, since experts in various fields distinguish mainly those characteristics of stones that are most convenient in the implementation of a particular activity.

The classification of mineral raw materials can be carried out according to the following criteria: origin, chemical composition, crystallographic parameters of the structure of the crystal lattice, size, etc.

The classification of faceted jewelry stones can also be carried out according to various non-subordinate features: crystallographic features, physical properties, cost, healing properties (in Europe, eastern and western stones), purpose (for jewelry and products), processing methods, etc.

The first scientifically substantiated classification of jewelry stones was proposed by the German scientist K. Kluge (1860), who divided jewelry stones into two groups and five classes: truly precious and semi-precious stones. In the first group, he attributed the stones of I, II and III classes, in the second - IV and V classes.

First group

I class: diamond, corundum, chrysoberyl, spinel.

Class II: zircon, beryl, topaz, tourmaline, garnet, noble opal.

Class III: cordierite, vesuvian, chrysolite, axinite, kpanite, staurolite, andalusite, chpastolite, epidote, turquoise.

Second group

Class IV: quartz, chalcedony, feldspars, obsidian, lapis lazuli, diopside, fluorite, amber.

Class V: jadeite, jade, serpentine, agalmatolite, satin spar, marble, selenite, alabaster, malachite, pyrite, rhodochrosite, hematite.

In 1896, M. Bauer proposed a new classification of jewelry stones, which was popular among jewelers and gemologists. In Soviet times, the classification of M. Bauer was reviewed and supplemented by Academician A.E. Fersman (table). The classification of M. Bauer - A.E. Fersman was used for a long time both in the USSR and abroad. All jewelry stones were divided into semi-precious stones, colored ornamental stones and precious stones of organic origin. The first two groups, in turn, are divided into three subgroups, which in the classification of these authors are called "order".

Classification of M. Bauer - A. E. Fersman

Group	Order	Name of stones
		Diamond, ruby, sapphire, emerald, alexandrite, noble spinel, euclase
		Topaz, aquamarine, beryl, red tourmaline, blood amethyst, almandine, uvarovite, jadeite, noble opal, zircon
Precious (gems)		Garnet, cordierite, kyanite, epidote, dioptase, turquoise, variscite, green tourmaline, rock crystal, smoky quartz, light amethyst, chalcedony, agate, carnelian, heliotrope, chrysoprase, semi-opal, sunstone, moonstone, labradorite, nepheline, sodalite, obsidian, titanite, benitoite, prehnite, andalusite, diopside, scapolite, thomsonite, hematite, pyrite, cassiterite, quarn with gold

Due to changes in the market value of stones, the scale of mining, etc., the classification below (table) required some adjustment. In 1973, E. Ya. Kievlenko proposed a revised classification by M. Bauer - A. E. Fersman (table).

Consideration of the above classifications of jewelry stones shows that as knowledge about stones accumulated, the classifications of jewelry stones were supplemented and refined. The most successful is the division of stones into jewelry, jewelry and ornamental and ornamental, which reflects the main feature of the classification - the purpose.

Thus, the classification of jewelry stones proposed by E. Ya. Kievlenko and based on the cost and purpose of jewelry minerals is the most complete, however, it is not without some contradictions.

For example, in 1978 a mineral called charoite was discovered (Chara River, Chita region), which became one of the most popular stones both in the USSR and abroad. It is used as inserts in rings, bracelets and earrings, as well as for the manufacture of caskets, vases, bowls and writing instruments. The texture of the mineral, color, transitions of shades from blue to lilac and white, mother-of-pearl shine look great in products that have fairly large flat or oval-round surfaces. The wealth of new deposits of charoite allows mass production of many products, however, the mineral is not in the classification of E. Ya. Kievlenko, since it was discovered later.

The same can be said about the simbircite discovered in 1985, named after its only deposit near the city of Ulyanovsk (Simbirsk).

Classification E. Ya. Kievlenko

		Name of stones
Jewelry (precious stones)		Ruby, emerald, diamond, blue sapphire Alexandrite orange, green and purple sapphire, noble black opal, noble jadeite Demantoid, spinel, noble white and fire opal, aquamarine, topaz, rhodolite, tourmaline Chrysolite, zircon, yellow, green and pink beryl, kunzite, turquoise, amethyst, pyrope, almandine, moon and sun stone, chrysoprase, citrine
jewelry ornamental		Lapis lazuli, jadeite, jade, malachite, charoite, amber, rock crystal (smoky and colorless) Agate, amazonite, hematite-bloodstone, rhodonite, opaque iridescent feldspars (belomorite, etc.), iridescent obsidian, epidotgarnet and vesuvian rodingides (jade)
ornamental		Jasper, marble onyx, obsidian, jet, petrified wood, larchite, patterned flint, graphic pegmatite, fluorite, aventurine quartzite, selenite, agalmatolite, colored marble, etc.

Therefore, the practical work of a merchandiser is associated with the need to study the properties of minerals of each group and newly discovered ones in order to attribute new materials to one position or another. In addition, it is necessary to study the internal classification of each of the minerals included in the table, since, for example, for opals and garnets, the name of the stone does not yet indicate the absolute belonging of all garnets and opals to the precious group.

An example is the internal classification of garnets.

I order - pyrope (dark red), almandine (purple-red), uvarovite (emerald green);

II order - spessartine, grossular, andradite.

However, the variety of andradite (demantoid) belongs to the 1st order garnets. It is one of the most valuable minerals in the garnet group, having a green color with various shades.

It is even more difficult to deal with the minerals of the opal group. All opals are divided into ordinary colorless ones without iridescence (iridescent play of light) and noble ones with iridescence. So, fire (solar) and black opal with iridescence are noble stones, therefore they are, naturally, precious jewelry minerals. Cacholong - from the group of opals without iridescence, classified as jewelry and ornamental stones, figurines, caskets, vases, etc. are made from it. Praz, hyalite, hydrofan, etc. also belong to ignoble opals.

There are varieties of corundum belonging to the II and III orders of precious stones. So, transparent rubies and sapphires are precious stones of the 1st order, and opaque ones are classified as 3rd order. Translucent rubies and sapphires with the effect of asterism (star stones) - stones of the II order.

Spinel is assigned to the group of jewelry (precious) stones of the III order, but we are talking only about the “noble” spinel of red and dark red color, which in ancient times was called “lal” in Russia. Other types of spinels are classified as stones of the IV order.

Diamond, in accordance with its purpose, is divided into jewelry and technical (board). Board - these are microscopic diamonds, devoid of a clearly defined color, opaque, they are crushed and used as an abrasive powder. There is a classification of technical diamond. Here are some of its varieties: ballas - radial-radiant aggregates, having a rounded shape, without inclusions; carbonado is a mixture of microcrystalline diamond and amorphous silica. E. Ya. Kievlenko's classification includes only gem-quality diamonds.

High cost is a characteristic feature of true gems. A subjective assessment of beauty, color, play of stone - all this leads to the fact that jewelry with high aesthetic properties is made from ornamental stones.

An equally important feature may be the scale of open deposits of a particular stone, which affects the availability and cost.

In production, the most convenient technological classification developed by the All-Russian Research Institute of Jewelery Industry, which is based on the sign of unity (or similarity) of stone processing methods. In it, all jewelry and ornamental stones are divided into three types: jewelry, jewelry and ornamental and ornamental, which, in turn, are divided into subtypes and groups according to transparency, hardness (on the Mohs scale) and other properties (table).

Technological classification of jewelry stones

	Subtype	Group	Name of stones
I. Jewelry stones	Subtype 1-1. transparent stones	Group 1-1-1. Hardness 10
		Group 1-1-2. Hardness 7-10	Corundum, beryl, tourmaline, garnet, chrysoberyl, spinel, topaz, quartz single crystals, euclase, phenakite, zircon, cordierite, andalusite, staurolite

I. Jewelry stones	Subtype 1-1. transparent stones	Group 1-1-3. Hardness less than 7, up to 5	Spodumene, chrysolite, kyanite, dioptase, brazilianite, tanzanite, chromium diopside, apatite, benitoite, axinite, scapolite, thomsonite, danburite, ulexite, cassiterite, hambergite, actinolite, green obsidian
		Group 1-1-4. Hardness less than 5	Sphalerite, fluorite, brucite, zincite, scheelite
	Subtype 1-2.	Group 1-2-1. Homogeneous	Blood hematite, pyrite, cobaltite, psilomelane
	Opaque, sparkling stones	Group 1-2-2. Figured	Hematite Goethite Glass Head, Cryptomelane Hollandite Glass Head
	Subtype 1-3. translucent stones	Group 1-3-1. brightly colored	Carnelian, chrysoprase, chloropal, rose quartz, colored semi-opals, smithsonite, prehnite, zoisite, translucent jadeite
		Group 1-3-2. With a pattern or beautiful inclusions	Agate, hairy, flywheel, onyx (sardonyx, carneolonyx)
		Group 1-3-3. Without drawing and coloring	Chalcedony, semi-opal, cacholong
		Group 1-3-4. Pseudo-chroic with specific orientation	Noble opal, moonstone, iridescent obsidian
	Subtype 1-4. Opaque matte with a beautiful color and dense surface texture	Group 1-4-1. Applied products with post-processing	Turquoise, variscite, coral
		Group 1-4-2. Applied naturally

Type II. Jewelry and ornamental stones	Subtype II-1. Viscous stones, hardness over 6	Group II -1-1.	Nephrite, jadeite and their hard natural imitations, garnet-chlorite rock, xenolith, fibrolite
	Subtype II-2. Stones of medium viscosity, hardness 5-6	Group II-2-1. brightly colored	Lapis lazuli, rhodonite, amazonite, jasper, unakite (an aggregate of epidote and potassium feldspar), charoite
		Group II-2-2. Figured	Petrified wood, graphic pegmatite, patterned flint, jasper, obsidian, heliotrope, perilith
		Group II-2-3. Pseudo-chroic	Belomorite, falcon and tiger eye, silvery obsidian, aventurine, mother-of-pearl
		Group II-2-4. Applied naturally	Subgroup II -2-4 a. Massive stones: kidneys of chalcedony, smithsonite, jade. Subgroup II-2-4 b. Crusts and outgrowths: amethyst and quartz brushes, uvarovite crusts, dendrites of manganese minerals, native copper and silver
	Subtype II-3. Small and medium hard stones	Group II-3-2. cold processed	Malachite, azurite, serpentine, anthracite
Type III. ornamental stones	Subtype III-I. Hardness over 5	Group III-1-1. glassy	Obsidian, jasper, hornfelses, microquartzites, ferruginous hornfelses
		Group III-1-2. Heterogeneous rocks and mineral aggregates	Subgroup III-1-2 a. Ice quartz, quartzite taganai, amazonite granite. Subgroup III-1-2 b. Peridotites, pyroxenites, hedenbergite skarn.

			Subgroup III-1-2 Eclogite, garnet gneiss, tourmaline-bearing rocks. Subgroup III-1-2 e. Granitoids, nepheline syenites, labradorite, porphyries, etc.
	Subtype III-2. Hardness 5 to 3	Group III-2-1. translucent	Onyx aragonite and calcite, fluorite
		Group III-2-2. Opaque	Marbles, ophiocalcite, anhydrite, serpentine, chlorite-serpentine rock
	Subtype III-3. Soft, hardness less than 3	Group III-3-1. translucent	Alabaster, selenite, halite
		Group III-3-2. Opaque	Graphite, soapstone, pyrophyllite, brucite, steatite

However, for examination, this classification is the least convenient, since it does not take into account cost characteristics. So, for example, type I - jewelry stones - includes high-value gems (diamonds, corundum, beryls) and relatively low-cost ornamental stones (fluorite, hematite, pyrite, apatite, green obsidian, jadeite, cacholong, chalcedony and a number of others) .

According to the classification adopted in retail price lists and purchase price lists, natural stones are divided into precious, semi-precious and ornamental.

Precious and semi-precious stones are the most expensive. They have a number of specific properties that determine their special visual appeal: transparency, brilliance, color, light refraction, dispersion, and others. In addition, their low prevalence and eccentricity make them even more attractive. The market value of gemstones depends both on the merits of the stone itself and the influence of fashion.

The main distinguishing feature of ornamental stones is their beautiful coloring or intricate decorative pattern. Their advantages are best manifested in stone-cutting products with polished surfaces (vases, caskets, candlesticks, etc.). Due to the variety of shades and decor, ornamental stones can be used for artistic and mosaic works, as well as architectural and facing material.

To regulate foreign trade operations, a special classification is used, presented in the Commodity Nomenclature for Foreign Economic Activity of the Russian Federation. In accordance with the TN VED RF, jewelry stones belong to group 71. (Section XIV) “Natural or cultured pearls, precious or semi-precious stones, precious metals, metals clad with precious metals, and products made from them; bijouterie; coins" and occupy the following headings:

7101 - Natural or cultured pearls, whether or not worked, whether or not sorted, but not strung, loose or loose; natural or cultured pearls temporarily strung for ease of transport.

7102 - Diamonds, whether or not worked, but loose or loose.

7103 - Precious (other than diamonds) and semi-precious stones, whether or not worked, whether or not sorted, but not strung, set or loose; unsorted gems (other than diamonds) and semi-precious stones temporarily strung together for ease of transport.

7104 - Precious or semi-precious stones, artificial or reconstructed, whether or not worked, whether or not sorted, but not strung, set or loose; unsorted artificial or reconstructed precious or semi-precious stones temporarily strung together for ease of transport.

7105 - Powder and powder of natural or artificial precious or semi-precious stones.

It must also be borne in mind that the value of a stone (and hence the price) at different times among different peoples was associated with their religious and national characteristics. Some stones were considered medicinal. So, in India, the ruby ​​is considered a sacred stone, a rare Indian will decide to sell a previously purchased ruby. Turquoise is very popular in the Muslim world. The Persians considered garnets to be royal stones, they carved the profile of the ruler on the surface of the stone, they wore it as an amulet to protect against accidents during travel. Carnelian in the 5th century in Cyprus it was used to treat tumors and sword wounds. In Russia, it was believed that carnelians contribute to wealth, give their owner strength, especially creative ones. A large gold ring with a carved carnelian insert was A. S. Pushkin's favorite talisman. The poet wrote about this stone:

"Dear friend! From the crime

From heart new wounds,

From treason, from oblivion Save my talisman!

The list of examples of the mystical and healing properties of various stones can be continued indefinitely, but, in spite of everything, the main feature of any classification is the purpose, which should determine the degree of preference in the product of one or another stone.

Characteristics of gems

Diamond - crystalline carbon, the most common form of crystals is an octahedron; in addition, a cube, rhombic dodecahedron or hexatetrahedron is possible. In synthetic diamonds, one can also observe a combination of an octahedron and a cube, that is, the so-called cubo-octahedron. The name of the diamond comes from the Greek "adamas" - irresistible, invincible. This amazing mineral has been known to people for more than five thousand years. However, to date, it has attracted close attention. Describing a diamond, you can use the word “most” dozens of times - the hardest, the most wear-resistant, the most thermally conductive, the most brilliant, the most expensive, etc.

A pure diamond is transparent, colorless, however, diamonds of the so-called fancy colors can be found: pink, orange, yellow, green, blue, black and brown. The presence of color is due to defects in the crystal lattice of the mineral, when carbon atoms replace some other chemical elements. For example, the presence of nitrogen gives a brown tint, boron - blue. Black color can occur either with a large number of dark-colored inclusions (for example, graphite), or in the presence of sulfide compounds.

Mohs hardness - 10.

Density - 3.52 g / cm 3.

Glitter is diamond.

The refractive index is 2.417.

Dispersion - 0.025.

Cleavage - high, on an octahedron.

Diamonds are divided into jewelry and technical. The main deposits are Namibia, Russia, Australia, South Africa, Brazil, India, Canada.

Beryls are silicates of beryllium and aluminum (Be 3 Al 2 (Si 6 O l6)). The most common form of crystals is a prism or pyramid. Pure beryl is colorless (goshenite), however, beryllium and aluminum can be replaced by various chemical elements (lithium, cesium, sodium, iron, fluorine, etc.), which leads to a wide palette of colors found in beryl.

Depending on the color, the following varieties of beryl are distinguished:

a) aquamarine (Fe 2+ /Fe 3+) - blue, light greenish blue, bluish green. The main deposits are Brazil, Mozambique, Nigeria, Russia, Afghanistan, Pakistan, India;

b) emerald (Cr 3 +) - from grassy green to dark green. The main deposits are Colombia, Brazil, Zambia, Zimbabwe, India, Pakistan, Russia;

c) sparrow or morganite (Mn 3+) - pink. The main deposits are Afghanistan, Madagascar;

d) heliodor (Fe 3+) - yellow, yellow-green. The main deposits are Namibia, Madagascar;

e) goshenite - colorless. The main deposits are Brazil, USA.

Sometimes emeralds, aquamarines and morganites can be found with the effect of "cat's eye" and with asterism (star effect). The star effect is extremely rare in beryl, but it can be seen, for example, in the beryl of Siberia, the dark brown beryl of Brazil, the black beryl of Mozambique. The appearance of the effect of a six-pointed star in beryl is associated with oriented inclusions of the mineral ilmenite.

Main physical characteristics:

Mohs hardness - from 7.5 to 8.

Density - 2.68-2.87 g / cm 3.

Luster - glass.

Refractive index - n e \u003d 1.562-1.593,

n 0 \u003d 1.568-1.604.

Birefringence - from -0.004 to -0.010.

Dispersion - 0.009-0.013.

Turquoise is a basic copper and aluminum phosphate containing water of crystallization. The name comes from the Persian "firuza", which means "flower". Crystals are extremely rare and only found in certain deposits, for example, in the state of Virginia (USA). Turquoise is opaque, but can show through in thin layers. Color - from bright, sky-blue to apple-green and greenish-brown. The blue color is provided by the presence of copper ions; when copper is replaced by iron or chromium ions, green shades are enhanced. Turquoise often has brown or black veins. Turquoise can discolor (chalk) with prolonged exposure to the sun. Over time or under the influence of alcohols, perfumes, aromatic oils, fats, soap suds, turquoise "ages", loses its luster and acquires a greenish-brown color.

Main physical characteristics:

Mohs hardness - from 5 to 6.

Density - 2.76 (2.30 -2.85) g / cm 3

Glitter - waxy.

Refractive index - 1, 610.

Birefringence - 0.040.

The main deposits are Egypt, Iran, Afghanistan, Peru, USA, Mexico, Tanzania.

Grenades. The name comes from the Latin granum - grain. The most common crystal shape is the rhombic dodecahedron. In nature, garnets are common, but gem-quality specimens are very rare, since garnet grains are very small. They are silicates of aluminum, iron, calcium, magnesium, manganese, chromium, less often titanium. Most often transparent or translucent. Mohs hardness - from 7 to 7.5. The luster of most garnets is glassy. Physical properties are varied (table).

The main representatives of the garnet group and their main physical properties

	Chemical formula	Color	Density, g/cm 3	Coefficient refraction
	Mg 3 Al 2 (SiO 4) 3	red, dark red
Almandine	Fe 3 Al 2 (SiO 4) 3	red with purple over color
Spessartine	Mn 3 Al 2 (SiO 4) 3	red, red-brown, red-brown, red-orange
Grossular	Ca 3 Al 2 (SiO 4) 3	yellow, yellow-green, green
Uvarovite	Ca 3 Fe 2 (SiO 4) 3	emerald
Demantoid	Ca 3 Cr 2 (SiO 4) 3	grassy to dark green
	Ca 3 Ti 2 (SiO 4) 3

Main deposits:

a) almandine (carbuncle, noble pomegranate) - India, Sri Lanka, Thailand, Russia;

b) pyrope (like fire) Australia, Norway, Russia (Yakutia), South Africa, USA, Czech Republic (in the Central Bohemian mountains, pyrope has been mined from the 13th century to the present);

c) spessartine - Namibia, Nigeria, Tanzania, Pakistan, USA;

d) grossular (Pakistani emerald) - Tanzania, Kenya, Mexico, India;

e) uvarovite (Ural emerald) - was first discovered in the middle of the 19th century. in the Urals, later individual specimens were found in the USA, Finland and Canada;

f) demantoid - Russia, Namibia, Italy;

g) melanitis - USA, Mexico.

Corundum- aluminum oxide (Al 2 O 3), which forms various crystal lattices and has a wide palette of colors. Pure corundum (leucosapphire) is colorless and transparent. Partial substitution of aluminum ions for chromium ions in the crystal lattice colors the crystal red (ruby) and pink (pink corundum). Partial substitution with titanium and ferrous iron gives blue (sapphire) and blue (blue corundum) color. The presence of ferric iron causes a yellow and green color (yellow and greenish corundum); chromium and ferric iron - orange and pink-orange (padparadscha). There are star-shaped rubies and sapphires (asterics) with six and twelve-pointed stars. Asterism in these stones is due to inclusions of needle-shaped rutile crystals. Very rarely corundums with the effect of "cat's eye" can be found. Even less common are chameleon corundums (sapphires), which are blue in daylight, and red-blue to red in evening light. Among minerals, corundum is second in hardness and abrasive ability after diamond. In terms of optical properties (brilliance, light refraction and dispersion), they are also inferior to diamond, but not a single stone can compare in color with blue sapphire or fiery red ruby.

Main physical characteristics:

Mohs hardness - 9.

Density - 3.90 - 4.05 g / cm 3

Luster - glass.

Refractive index - n e \u003d 1.762 (1.758-1.770),

n o \u003d 1.770 (1.766-1.780).

Dispersion - 0.011.

Cleavage - absent.

Main deposits:

ruby - Burma, Vietnam, Thailand, Tanzania, Sri Lanka, Pakistan, India, Nepal, Afghanistan, Tajikistan, Tanzania, Kenya, Colombia;

sapphire - Australia, Burma, India, Cambodia, USA, Thailand, Sri Lanka, Vietnam, Nigeria, Madagascar.

quartz group- silicon dioxide (Si0 2), the most common form of crystals is a prism. Among all minerals, quartz (along with feldspars) is the most common in nature. It occurs both as well-formed crystals and as drusen. In addition, rocks are used in jewelry, consisting mainly of quartz - jasper and quartzites. All numerous varieties of quartz can be divided into crystalline (macrocrystalline) and cryptocrystalline (micro- and cryptocrystalline). Pure crystalline quartz (rock crystal) is colorless, transparent or milky white. Numerous variations in the color of quartz can be due to: the presence of color centers (due to the substitution of Si 4+ with other chemical elements), the presence of certain optical effects, or the presence of inclusions (table).

The main representatives of the quartz group

Mineral name	Color	Reasons for staining
macrocrystalline
Rhinestone	colorless	-
Amethyst	violet	Fe 4+ - centers
Smoky quartz (morion)	smoky black, smoky brown	AlO 4 + electron
rose quartz	pink	Ti 3+ - centers
Citrine	lemon yellow	Al O4 - centers
Micro- and cryptocrystalline
Aventurine	green, yellow-green, yellow-brown	inclusion
Chrysoprase	green	inclusion of nickel silicates
Cornelian	orange, red, brown	inclusions of some minerals: hematite, gotite, etc.
Heliotrope	green with red spots	inclusions of chlorides of various metals and hematite
Onyx	zone-colored, yellow, green, brown	inclusions of manganese oxides
Agate		varied
Jasper	almost all colors, zone-colored	varied

Zone-colored quartz can be found in nature. For example, the color of smoky quartz is due to the fact that trivalent aluminum in the crystal lattice is replaced by the so-called "Morion" center (AlO 4 + electron). This color is stable at temperatures not exceeding 180 °C. At higher temperatures, the reverse substitution takes place, and the quartz becomes discolored again. Thus, there are partially dark, partially colorless transparent crystals, as well as crystals with a zone-different degree of severity of the dark color.

There are quartzes with an iridescent effect: cat's eye (green), bull's eye (red, brown), tiger's eye (yellow) and hawk's eye (gray, black).

Sometimes (very rarely) in quartz you can observe the effect of asterism in the form of a six-pointed star, which is due to the presence of needle inclusions of minerals such as gotite, rutile or sylmanite.

It is quite common for quartz to have macro-inclusions of various nature, which form certain patterns inside the crystal. For example, differently oriented rutile crystals within a rock crystal can create a so-called "frost pattern"; needle inclusions of hematite - a pattern of parallel lines (the so-called "beetle legs"); inclusions of metal chlorites (green), manganese oxide (black) and hematite (red, brown) can create a pattern known as "mossy".

The chameleon effect is observed in quartz rather as an exception. However, "Russian amethysts" from the Murzinka deposit (Urals) gained fame and worldwide recognition precisely for the ability to change color from purple (daylight) to rich wine-red (artificial lighting).

Main physical characteristics:

Since quartz is one of the most common minerals on Earth, it is quite difficult to identify the main deposits - quartz is found all over the world. Brazil can be called one of the most significant suppliers of jewelry quartz for the world market (amethysts, rock crystal, citrine, smoky quartz (morion, rauchtopaz), agate). Also from the South American states can be called Uruguay (amethysts, agates) and Bolivia (amethysts, citrines). On the African continent, Zambia has one of the largest deposits of amethysts in the world, Namibia has many different deposits (rock crystal, smoky quartz, citrine, rose quartz, amethysts and agates). Rich deposits are also found in South Africa (rock crystal, smoky quartz, citrine, amethyst, agate, carnelian, heliotrope and chrysoprase) and Madagascar (rock crystal, smoky quartz, amethyst, citrine, rose quartz, agate, aventurine and jasper). In Asia, the most significant quartz mining is carried out in India (amethysts, agates, heliotropes, aventurines). Of the European countries, one can name Poland (the largest deposit of chrysoprase in the world) and Germany (mining of amethysts, agates and jaspers has been carried out in the Idar-Oberstein region since the 14th century). Russia for almost 200 years (until the middle of the 20th century) was the world's largest supplier of amethysts to the world market, in Russia there are deposits of all varieties of the quartz group.

Opal consists of silica and water (SiO 2 - nH 2O). Over time and when heated, water of crystallization can be lost, causing the stone to become cloudy. The color of noble opal is white, gray or black, and the main advantage is opalescence, i.e. ability to repeatedly scatter incident light.

Noble opals are divided into:

a) white opal - white base with iridescence;

b) black opal - dark base with iridescence;

c) fire opal (or sunny) - transparent and translucent, reddish or orange, opalescent, sometimes with iridescence;

d) cat's eye (a very rare and most expensive variety) - bright green and greenish with concentric zonal opalescence;

e) royal opal - with a dark red or bronze core, an emerald green border and an unpainted outer zone;

f) girasol is a translucent bluish or bluish-white opal with reddish-golden opalescence.

In addition, there are ordinary (non-precious) opals that do not have opalescence. For example, cacholong is a light, porcelain-like opal. Layered opals are called agate opal or onyx opal.

Main physical characteristics:

Mohs hardness - from 5.5 to 6.5.

Density - 1.97-2.22 g / cm 3.

Luster - glass.

Refractive index - 1.450 (1.370-1.470).

The main deposits are Australia (95% of the world's opal production), Peru, Kazakhstan, Mexico, Russia, USA, Slovakia.

Topaz- fluorine-containing aluminum silicate (Al 2 (FOH) SiO 4). There is an assumption that the name of the mineral comes from the Sanskrit "tapas" - fire. In Russia, topaz was called "Siberian diamonds". The oldest piece of jewelry found at one of the sites of the most ancient man in the Urals is a product made of rock crystal and topaz. Topaz is characterized by a special inner play of light, with its lightness and transparency reminiscent of dew drops.

The color of topaz is very diverse: yellow, wine, honey and golden yellow, blue, bluish-green, green, pink, red (Brazilian rubies), purple, absolutely colorless stones are rare. Topaz crystals can have a cat's eye effect. Sometimes topaz has a heterogeneous color, for example, in the central part of the crystal it is colored blue, and on the outer faces it is pinkish-yellow. In addition, topazes have the ability to change their color. When heated, brown and yellow topazes become pink, colorless - as a result of UV irradiation - brown, and with simultaneous exposure to UV irradiation and temperature - sky blue.

Main physical characteristics:

Mohs hardness - 8.

Density - 3.52-3.57 g / cm 3.

Luster - glass.

Refractive index - n x \u003d 1.606-1.635,

n y \u003d 1.609-1.637,

n z \u003d 1.616-1.644.

Birefringence from 0.008 to 0.010.

Dispersion - 0.008.

Cleavage - perfect cube.

Topazes of Brazil and Russia are the most famous (the largest topaz weighing 32 kg was found). Deposits are also found in Australia, Burma, Pakistan, USA, Japan.

Rauchtopaz does not belong to the topaz group, since it is smoky quartz - a representative of the quartz group.

Tourmaline is a complex aluminum borosilicate of alkali metals (lithium, sodium), as well as calcium, magnesium, manganese and iron. Contains water and fluorine. Tourmalines enriched in alkali metals are usually colorless. However, the popularity of tourmaline is associated with the beauty of the diverse colors of its various transparent varieties:

a) rubellite - pink or red;

b) siberite - cherry red;

c) indicolite - blue or blue;

d) verdelite - green;

e) dravite - brown, yellow and brown;

f) achroite - colorless;

g) schorl - black.

There are tourmalines with the effect of pleochroism (two shades of the primary color in one crystal), as well as with asterism (very rare). Asterism is observed in green-colored tourmalines, and is usually caused by the presence of thin channels in the stone filled with gas-liquid inclusions.

Main physical characteristics:

Mohs hardness - from 7 to 7.5.

Density - 3.05 (2.90-3.40) g / cm 3.

Luster - glass.

Refractive index - n e \u003d 1.620 (1.614-1.639),

n o - 1.640 (1.634-1.666).

Birefringence - 0.020 (0.014-0.032).

Dispersion - 0.009-0.011.

Cleavage - absent.

The main deposits are Burma, Brazil, Namibia, Russia, USA, Sri Lanka, Afghanistan.

Zircon - zirconium silicate (Zr (SiO 4)). According to optical properties, zircons are divided into three types:

1) Siamese diamonds (yellow, straw yellow and smoky zircons);

2) hyacinths (red, yellow-orange, raspberry-orange, brown-red and brown zircons);

h) colorless and bluish zircons. They are sometimes used as imitation diamonds.

Main physical characteristics:

Mohs hardness - from 6.5 to 7.5.

Density - 3.91 -4.73 g / cm 3.

Luster - glass.

Refractive index - n e \u003d 1.923-1.960,

n o \u003d 1.968-2.015.

Birefringence - 0.045-0.055.

Dispersion - 0.022.

The main deposits are Vietnam, Kampuchea, Madagascar, Thailand, Sri Lanka, Nigeria, Tanzania.

Spinels - magnesium aluminate (MgAl 2O3), a typical crystal shape is an octahedron. Spinels can have a wide variety of colors: all shades of pink and red, blue, blue, green, yellow, brown, purple, orange, lilac, purple, dark brown (ceylonite), black. There is a colorless spinel, spinel with an alexandrite effect, with asterism in the form of four and six-pointed stars. In ancient times, red spinel was considered a ruby, but in its structure and basic physical properties it differs from corundum, for example, hardness, density and refractive index are slightly lower.

Main physical characteristics:

Mohs hardness - 8.

Density - 3.54-3.90 g / cm 3.

Luster - glass.

Refractive index - 1.718 (1.711-1.742).

Birefringence - from -0.007 to -0.010.

Dispersion - 0.011.

Cleavage is perfect.

The main deposits are Afghanistan, Tajikistan, Vietnam, Burma, India, Madagascar, Tanzania, Thailand, Sri Lanka.

Properties of jewelry stones

Many jewelry stones are characterized by the same or similar features. So, for example, among transparent stones, groups of the same color can be distinguished - green, red, etc. Therefore, it is difficult to determine the nature of the stone only by color and transparency. To assign a mineral to one or another type, a special diagnostic is carried out, based on the determination of a number of physical, chemical and morphological (crystallographic) indicators.

The most important are physical indicators, which include color, gloss, transparency, refraction and birefringence, dispersion, luminescence, hardness and density.

Color of gemstones Coloration is one of the most characteristic distinguishing features for most minerals. The color of the main minerals is presented in table.

Color of gemstones

Transparent and translucent
			Vorobevit
	Rhinestone
			morganite
	Leucosapphire
			rose quartz
	Almandine		rubellite
	fire opal
			Tourmaline
			Verdelite
			Grossular
Orange	Subparadscha		Demantoid
	Cornelian
Brown	Hessonite		Tsavorite
	Morien (Rauchtopaz)		Tourmaline
	Spessartine		Uvarovite
Violet	Almandine		Chrysolite
			Chrysoberyl
			Chrome diopside
	Tanzanite		Aquamarine
			Tanzinite

	Heliodor
	Hessonite
	Grossular		Benitoite
			Tanzanite
Opaque and translucent in thin layers
	Anhydrite
	Cacholong
			Rhodochrosite
		Brown	Aventurine
			Bulls-eye
	cat eye		Obsidian
			Eye of the Tiger
			Amazonite
			Heliotrope
Violet
			Chalcedony
			Chrysoprase
	Obsidian

It is known that visible light consists of seven pure colors, differing in wavelengths from 380 to 740 nm. The reason for the diverse coloration is the unequal degree of reflection and absorption of various waves of the light spectrum. A stone that transmits the entire spectrum of the visible range seems colorless, absorbing the entire spectrum - black. If a stone reflects only the red part, and absorbs the rest of the spectrum, then it is red, etc.

The color of gemstones depends on the lighting, since the spectra of solar and artificial light have some differences. The sharpest change in color under different lighting is expressed in chameleon stones, for example, alexandrite.

Transparency

Transparency is understood as the ability of a solid body to transmit light rays through itself to one degree or another. Transparency depends on the degree of perfection of the crystal structure, the presence or absence of cracks, solid and gas-liquid inclusions larger than the wavelength of the incident light, which distort the path of rays through the stone. If the inclusions are large, the stone becomes opaque.

Transparency is determined visually when viewed through the light or experimentally. Quantitatively, the degree of transparency, i.e., the value of the transparency coefficient and absorption coefficient, can be set using spectrophotometers.

According to the degree of transparency, jewelry stones are divided into:

Transparent - all colorless and slightly colored, through the plates (3-5 mm thick) of which the object is clearly visible;

Translucent, through the plates of which objects are not clearly visible;

Translucent in thin layers;

Opaque.

Shine

Glitter characterizes the reflectivity of the surface of the mineral and depends on the refractive index and the nature of the surface of the stone.

The following terms are used to describe gloss:

Diamond - with strong reflection of light from the surface (diamond, zircon, demantoid);

Glass - glass-like luster (typical for most transparent gems, for example, corundum, beryls, topazes, tourmalines);

Wax - with an almost matte surface (turquoise, jadeite, coral, jasper);

Bold - the surface of talc and jade;

Metallic - strong luster of the surface of opaque minerals (pyrite, hematite);

Mother-of-pearl - the brilliance of pearl shells;

Resinous - shine of amber;

Silky - gloss from a fibrous surface (selenite, some varieties of calcite).

Hardness

Hardness is the resistance of materials to local plastic deformation that occurs when a more solid body (indenter) is introduced into it. Most often, for minerals, it is measured on the relative Mohs hardness scale. As hardness standards in this scale, 10 minerals are used, which have their own hardness, estimated in points (table).

Mohs hardness scale

Any gem can be scratched by a mineral that is harder on the Mohs scale.

Density

The density of a substance is determined by its mass per unit volume and is related to the packing density of the atoms or molecules of the substance.

The values ​​of hardness and density of various minerals are presented in table.

Density and hardness of gemstones

Name	Density, g / cm 3	Hardness (Mohs)
Aventurine
Aquamarine
Alexandrite
Diamond
Demantoid
Black pearl
Obsidian

Refraction

Refraction is a change in the direction of light rays when they pass (at an angle other than 90 °) through the interface between two media (for example, air and a mineral) with different optical characteristics. The greater the difference in the optical densities of the media, the stronger the rays are refracted.

A stick half lowered into the water at an angle other than 90 ° “breaks” at the surface of the water, i.e., its lower part receives a different direction. The degree of refraction of crystals is a constant value, therefore, it serves as one of the indicators for identifying precious stones. The speed of light in air is 300,000 km/h. The speed of light in a diamond is 124,120 km/h. The refractive index of diamond (300,000 / 124,120) = 2.417. The refractive indices of gemstones range from 1.4 to 3.2.

The refractive index is determined on a refractometer. The principle of operation of the device is based on the phenomenon of total internal reflection of light as it passes from a denser to a less dense medium. Knowing the refractive index of the prism-table on which the test sample is placed, and by measuring the critical angle at which total internal reflection begins, the refractive index of the sample is determined. Usually refractometers have a transparent measuring scale, visible through the eyepiece of the instrument, which is graduated in refractive index values. One part of the scale, on which the reflected rays fall, looks illuminated, the rest is darkened. The refractive index is read from the position of the edge of the shadow on the scale.

Single refractive crystals are called isotropic. These include diamond, spinel, garnets.

Birefringence

Birefringence of light is the decomposition of a light beam entering a crystal into two refracted beams with different refractive indices. The difference between these indicators characterizes birefringence - one of the indicators of crystal diagnostics.

The most pronounced double refraction is expressed in calcite, zircon, tourmaline, peridot. If the minerals mentioned above are transparent - birefringence - doubling of the faces can be observed with the naked eye - when viewing the edges of the lower faces of a faceted crystal through a table.

Dispersion

The color components of a white beam of light (red, orange, and others) have different wavelengths and are refracted differently in minerals, as they have different refractive indices. A measure of dispersion is the difference between the refractive indices for two selected wavelengths, one of which corresponds to red (687 nm) and the other to violet (430.8 nm).

In practice, most often it is not the absolute value of the dispersion of the refractive indices that is determined, but the so-called dispersion effect, i.e. the color play of faceted stones, which is established visually.

Strongly pronounced dispersion is characteristic of a limited number of gemstones (diamond, demantoid, zircon). For example, a diamond, which has a strong dispersion, creates a play of light - "diamond fire". Minerals that, like diamond, have high dispersion rates (zircon) are used as diamond substitutes, since not everyone can visually distinguish the “diamond fire” of zircon from the “diamond fire” of diamond.

Pleochroism

When light passes through birefringent minerals, its selective absorption is possible, i.e., there is a difference in the color of the mineral. The property of some gems to different absorption of each of the two refracted rays is called pleochroism. In uniaxial crystals, two colors can be observed - and then they speak of dichroism, and in biaxial crystals, three colors - trichroism. The instrument for observing pleochroism is the dichroscope.

Since pleochroism occurs only in colored birefringent crystals, this feature makes it possible to distinguish anisotropic crystals from isotropic ones (ruby from pyrope and almandine). Sometimes pleochroism creates additional attractiveness by displaying two- and three-colors on the platform (table) of a faceted crystal.

Luminescence

Luminescence is the ability of some minerals to emit light as a result of exposure to certain types of energy.

After a substance has acquired excess energy through irradiation, it can emit the so-called "cold" radiation, which is often a characteristic feature of a particular substance. Of the many types of luminescence, the most used in gemology is photoluminescence, which occurs when a substance acquires energy in the form of electromagnetic radiation (eg, visible light, ultraviolet rays, x-rays). Some gems luminesce when exposed to short or long wavelength light.

When irradiated with ultraviolet rays, the so-called fluorescence occurs (the name is associated with the mineral fluorite, in which the effect of luminescence in ultraviolet rays was first discovered). Fluorescence allows you to distinguish natural stones from synthetic ones, which react differently to ultraviolet rays.

Luminescence from exposure to X-rays makes it possible to distinguish natural pearls (do not luminesce) from pearls grown in fresh water, which are highly luminous.

Using the effect of luminescence, you can determine the place of extraction of the mineral. The same mineral mined in one deposit luminesces, mined in another does not.

The play of light in minerals

The optical effect caused by the reflection of light rays from the internal surfaces of the crystal is called the play of light.

Consider three types of play of light: iridescence, asterism and iridescence.

Iridescence is due to the reflection of light from inclusions lying parallel inside the mineral: asbestos or crocidolite. Iridescence is well observed when the mineral is illuminated by the rays of the sun or by the directed rays of an electric lamp, when the mineral is cut with a cabochon (domed processing of the mineral) or a bead. The effect appears as a luminous band that flickers when the mineral is rotated. Quartz minerals have iridescence, while, depending on the color of the base (color of the stone), they distinguish: cat's, falcon's, tiger's and bull's eye.

The cat's eye is a quartz of green, gray, greenish-gray color with an iridescent effect. The largest deposits of the cat's eye are located in Sri Lanka, India, in the Urals near the city of Zlatoust.

Hawkeye is a dark blue or light blue quartz with inclusions of crocidolite. Hawkeye deposits are located in South Africa.

Tiger's eye - golden yellow or brown quartz with goethite inclusions. Tiger's eye deposits are located in South Africa, Burma, India, Austria.

Bull's eye - red quartz with an iridescent effect. Bullseye deposits are located in South Africa.

Many minerals can have the effect of iridescence, among them: emerald, garnet, tourmaline, zircon, chrysoberyl (cymophane).

Asterism is due to the accumulation of small fibers or crystals that are oriented along the crystallographic axes, forming two, three or six such directions. When processing a mineral with a cabochon, the effect of a four-, six- and twelve-beam star is observed, the best effect is observed in sunlight or with directional lighting of an electric lamp. The effect of a four-ray star (two directions intersect at an angle of 90 °) is observed in diopside, whose location is in Madras (India). Hindus call diopside with the effect of asterism "Black Star" (black star).

Asterism in diopsides is due to inclusions of magnetite. The effect of a six-pointed star (three directions of inclusions intersect at an angle of 60°) is observed in corundum as a result of inclusions of rutile or hematite. In addition to corundum, asterism is observed in chrysoberyl, spinel, and garnet.

It is very rare to find sapphires with a 12-pointed star. One of these sapphires weighing 7.28 carats is in the collection of B. Anderson, author of the book "Gemstone Definition". Recently, a lot of synthetic rubies and sapphires have appeared, artificial sapphires are almost opaque, their star is very clear, looks like a painted one.

Irization is an iridescent play of light caused by the interference of light rays that are reflected from densely spaced balls on the surface and inside the mineral. As a result of this, white light, falling on densely spaced balls, decomposes into a spectrum and is seen as the colors of the rainbow reflected from the mineral. The effect of iridescence is observed in some types of noble opal: white opal - white base with iridescence, black opal - dark base with iridescence. The main deposit of precious opal is Australia, which supplies up to 90% of precious opal to the market. Findings of noble opal are known in India, Indonesia, Mexico and Brazil. Small deposits of opal in the Russian Federation are located in Kamchatka and Chukotka. Due to its low hardness (5.5-6.5 on the Mohs scale), opal should be protected from shock, sudden temperature changes, exposure to abrasive materials, cleaned only in soapy water, steam and ultrasonic treatments are unacceptable.

When determining chemical indicators, they study the chemical composition of the mineral, the presence and chemical composition of various internal inclusions, which can be solid, liquid, gaseous, or combined two- or three-phase. Usually, minerals of one type or another are characterized by certain inclusions, for example, pyrope or graphite inclusions are often present in diamond crystals, two-phase gas-liquid inclusions in emeralds, and inclusions of such minerals as hematite, rutile, and gothite are characteristic of the quartz group.

Morphological (crystallographic) indicators include the geometric shape of crystals (cube, prism, pyramid, octahedron, rhombic dodecahedron, etc.); twinning ability; color zoning and crystal growth lines, anisotropy, etc. One of the most important indicators of the structure of a mineral is cleavage.

Cleavage is the property of some crystalline substances to split along certain planes where there is a weaker chemical bond. Cleavage appears in many gems. Allocate imperfect, weak and perfect cleavage. For example, beryl, diamond and topaz, respectively.

False, or pseudo-cleavage, is the ability of a mineral that does not have cleavage to split in certain areas.

The occurrence of false cleavage may be associated with special conditions for the growth of the mineral (for example, for corundum) or with polysynthetic twinning of crystals (for example, labrador).

Processing of jewelry stones

Historically, nature itself suggested two main types of stone processing - cabochon and cutting.

Tumbling is the processing of minerals in a special tumbling drum, where the processed stones, abrasive material and liquid with special shampoos are placed.

The result is a streamlined stone without facets. The minerals obtained as a result of tumbling in jewelry are called cabochons.

Cabochon is a convex (dome-shaped) stone without facets. Produced by grinding and polishing the raw mineral.

By height, cabochons are divided into:

Low (d/2 minerals greater than its height);

Medium (d/2 mineral is close to its height);

High (d/2 mineral less than its height).

The shape of the cabochon is divided into types:

a) flat - domed shape on a flat base;

b) biconvex - resemble the shape of an egg;

c) convex-concave - saucer.

The latter type is used in the processing of translucent minerals, when it is necessary to use the play of light reflected from the thick walls at the top of the mineral and the thin walls of the cabochon at its bottom.

Cabochon processed:

1) opaque minerals (turquoise, charoite, rhodonite, malachite, jasper, serpentine, etc.);

2) minerals translucent in thin layers (jade, chrysoprase, onyx, agate, etc.);

3) translucent minerals (morion, moonstone, etc.);

4) minerals with effect:

a) opalescence (precious opals);

b) iridescence (cat, tiger, falcon, bull's eye);

c) asterism (ruby, sapphire, diopside).

Faceting is the processing of natural crystals (cube, octahedron, rhombic dodecahedron, etc.) in the form of polyhedra.

Each piece of cut stone has its own name.

The middle part of a faceted stone is called a girdle, which is a belt covering the largest section of the stone's circumference and dividing it into upper and lower parts. The word "girdle" (meaning "circle") arose in the cutting industry since the use of a roughing machine, which made it possible to give a diamond blank a round shape. The height of the girdle determines the quality of the cut. For example, high-quality full-cut diamonds should have a thin, uniform girdle (up to 1.5% of the diamond's diameter); medium-cut diamonds have a thicker girdle (up to 3% of the diameter), and, finally, low-quality diamonds can have a girdle thickness of up to 6.5% of the diameter. The plane of the girdle is usually called the plane passing through the middle line of the cylindrical part of the girdle and bounded by a circle, the diameter of which determines the diameter of the cut stone. This diameter serves as the initial value for calculating all the main elements of the cut (the height of the middle, upper and lower parts, the size of the platform).

The shape and size of the girdle determines the shape and size of the cut stone.

Platform - the upper face, located perpendicular to the axis of the stone, has the shape of a regular octagon and is designed to capture the light falling on the upper part of the diamond and reflect the outgoing light flux.

The upper part - the crown, is located between the sectional plane of the girdle and the upper face of the platform. The height of the crown of a faceted stone is determined by the distance from the plane of the girdle to the platform.

On the upper part (in the crown) of a full-cut diamond, in addition to the platform, 32 facets are placed with three belts - parts of a flat surface bounded by a closed broken line (ribs).

The bottom of the cut stone is called the pavilion. On the first belt from the girdle there are 16 triangular pavilion faces, called bottom wedges. On the second - 8 faces having the shape of a deltoid.

The edges of the bottom are reduced to a point called the spike of the diamond. In some cases, the spike can be cut off to form a plane called a culet, which is parallel to the site and repeats its shape. The centers of the platform, the planes of the girdle and the culet must lie on the axis of symmetry of the faceted stone.

In most jewelry, the bottom of the stone is set in a setting, and therefore the light does not fall directly on the bottom edge, but they play a major role in reflecting the light passing through the crown. The light passing through the platform and the main edges of the top is completely reflected from the edges of the bottom and, after refraction, exits through the main edges of the top and the platform.

The whole variety of cuts can be divided into traditional, fancy and mixed.

Assortment of traditional cuts

Diamond tip. The cutting is based on grinding and polishing the natural facets of the polyhedron, including the octahedron.

Diamond table. With the development of diamond processing technologies, it becomes possible to obtain additional facets. For example, in the "diamond table" cut, the upper vertex of the octahedron is cut parallel to the plane of the girdle and forms a table (platform). The lower top is polished to form a culet - a small plane, also parallel to the girdle.

Eight border. Over time, more complex forms appear. In the figure-eight cut (Kr-17), not only the upper and lower vertices of the octahedron are polished, but also its side faces. Thus, an octagonal table is obtained, surrounded by eight 4-angular crown faces; the pavilion consists of 8 triangular faces that converge to a single point called a thorn. The spike can be ground off, forming an additional face parallel to the plane of the girdle - a culet (Kr-18). This form is used for small diamonds, for inexpensive natural stones, as well as for various imitations.

The Swiss brilliant cut is also used for smaller stones (0.01 to 0.05 carats). It is a complicated figure-eight cut. The table is surrounded by eight faces, and in the crown there are eight additional lower faces. The pavilion has 16 faces.

Full brilliant cut, in which the stone has 57 (58) facets, including a table, a crown - 32 facets, a pavilion - 24 facets, is most applicable for medium and large transparent stones. The platform has the shape of an octahedron. The edges of the bottom are reduced to a point called a spike. Sometimes the spike is cut off and then a plane is formed that repeats the shape of the site and is parallel to it, which is called the culet - the 58th face. This type of cut is the most common for medium and large diamonds. It is also widely used for cutting colored precious and semi-precious stones and their synthetic counterparts.

With regard to a round diamond, M. Tolkovsky developed a brilliant cut that best emphasizes the natural beauty of the crystal, which is called the classic (or ideal) cut by M. Tolkovsky.

M. Tolkovsky established that in order to obtain the greatest brilliance and "play" of a round diamond, the cut must be performed in such a way that the optical properties of diamonds are maximally manifested. For this purpose, the following rules must be observed:

1) the angle of inclination of the sides of the bottom β should be such that the light falling on the platform and the main sides of the top is completely reflected from the sides of the bottom. In this case, the angle of incidence of the light beam φ on the inner faces of the bottom will be greater than 24.8 degrees (i.e., greater than the critical angle of the diamond);

2) the angle of inclination of the main faces of the top α must be such that the light reflected inside the diamond hits the edges of the top at an angle γ less than the critical one, and after refraction, the light leaves the crown of the diamond.

In accordance with these rules, M. Tolkovsky calculated the ratio of the sizes of various parts of a cut diamond. So, if the diameter of the girdle is taken as 100%, then to obtain the desired angles, the diameter of the platform should be 53%, the height of the crown - 16.2%, the height of the girdle - 1-2%, the height of the pavilion - 43.1%. This type of cut is most common in the United States.

Currently, there are other calculated ideal cuts: Brilliant cut of Epler, Johnson and Roech, Parker, Scandinavian brilliant cut. The parameters of ideal cuts are presented in the table.

Table

The main parameters of ideal cuts

Perfectly cut round diamonds are the most expensive, because only if the ideal proportions, based on the physical and optical laws of reflection and refraction of light in the crystal, are precisely observed during cutting, the stone acquires a maximum of sparkle and play.

However, the costs of producing ideal cut diamonds are also the highest. Since natural crystals in most cases do not have an ideal shape and proportions, a lot of waste is generated during manufacture.

The practical brilliant cut allows the most rational use of rough diamonds due to a wider range of tolerances of geometric parameters. Tolerances for practical cuts vary from country to country and also depend on the size of the stone and the cutting requirements of specific cutting companies or customers, or requirements set out in specific contracts. The most beautiful practical cut is the Russian brilliant cut, known all over the world under the Russian cut brand. The main cutting parameters are: girdle diameter 100%, table diameter 50-65%, crown height 10-16%, pavilion depth 40-45%, slope of crown facets 30-40°, pavilion 38-43°.

In addition to round cuts, the traditional ones include step cuts: baguette and emerald. These cuts are designed for fragile gems.

The baguette cut table has the shape of a square or rectangle, from which the edges of the crown, limited by the girdle, are located in steps. The edges of the pavilion are also arranged in steps, 4 on each tier. The edges of the pavilion can converge at one point and form a spike, or end with a culet. The emerald cut has an octagonal table (baguette with cut corners). Further, the edges of the crown and the pavilion are arranged in the same way as in the baguette, in steps, but eight facets on each tier.

Assortment of fancy cuts

All types of fancy cuts can be divided into 2 large groups: mass (popular) and exclusive. The range of popular fancy cuts and their quality requirements are well known. These types of cuts are made by various Russian and foreign cutting enterprises. Exclusive types of cuts include cuts created in each specific case individually at a single enterprise. The goals of creating certain exclusive fancy cuts may vary. It may be a desire to make the stone more expensive by increasing the cut yield. This may be a desire to expand the range of faceted inserts produced. However, most often, exclusive fancy cuts are developed by order of the client for a specific piece of jewelry or a specific stone.

Popular types of fancy cuts include such well-known shapes as marquise, oval, triangle, trilliant, princess, heart and some others, as well as derivatives of full brilliant and step cuts.

With fancy cutting, the shape of the girdle of the stone changes, the number of facets increases or decreases, the angles of inclination of the crown and pavilion faces to the girdle. This is due to at least two reasons:

The need to maximize the use of natural raw materials, which, with their size or defects, do not fit into the parameters of traditional cuts;

The desire of the consumer to have a precious stone with an original cut. Such a desire is often determined by the fashion for one or another type of fancy cut.

Full brilliant cut has been developed in the following types of fancy cuts.

1. Brilliant cut ELBA. With this type of cut, the stone has a full diamond 58-sided shape, but the edges are also applied to the surface of the girdle.

2. Royal cut - eighty-six-sided cut. The base is a full brilliant cut, but instead of an octagonal table there is a twelve-sided one; facets are arranged as follows - 49 crown faces (1, 12, 12, 24) and 36 pavilion faces (24, 12) plus a culet.

3. Cut Magna (or Majestic) - consists of 102 facets. The basis is a ten-sided table, the facets are arranged in the following order - 61 facets of the crown (1, 10, 20, 20, 10) and 61 facets of the pavilion (10, 20, 20, 10, 1). Stones cut with this type of cut have a very high brilliance.

4. Cut Imperial - unpaired cut. Developed by Maxime Elbe (Hamburg, Germany). It has an unpaired number of platform corners (9, 11 or 13), and, accordingly, an unpaired number of facets on each step of the crown and pavilion. For example - 37 crown faces (1, 9, 9, 18) and 27 pavilion faces (18, 9). This cut provides 23-30% more intense diamond "play" than a full brilliant cut.

5. Antique cut, or pillow. The cut is square or rectangular in shape along the girdle with rounded tops, has an octagonal platform and four levels of crown facets of 8 facets. The antique cut is one of the earliest cuts used for diamonds. This cut allows minimizing the amount of waste and, consequently, obtaining a cut diamond of a larger mass. Very often used in the cutting of Brazilian diamonds.

Cut wedges (cross) is a derivative of stepped forms. This modification of the emerald cut has a quadrangular table shape, around which triangular facets are arranged in three tiers. Wedge cutting is used to enhance the color of the stone.

Also a derivative of the step cut is the Princess cut. It has a quadrangular platform, crown faces in the form of triangular and quadrangular facets, and pavilion faces in the form of many narrow wedges radiating from the spine to the corners of the girdle. The number of these wedges determines the variety of the Princess cut. For example, Smolensky Crystal produces the following types of Princess cut: P-53, P-57, P-65, P-73, that is, with the number of facets - 53, 57, 65 and 73.

For the manufacture of profile cutting, thin plates are used, with a thickness of 1 to 2-3 millimeters. These plates can be cut from fragments of crystals, raw materials with common internal defects that need to be cut out, as well as cutting waste. The use of this type of cutting allows enterprises to use raw materials as efficiently as possible. The upper plane of the cut plate is polished, a series of V-shaped parallel grooves is applied to the lower one, which create the "game" of the mineral. According to the girdle, such a plate can have a wide variety of shapes, but the most popular is the “heart” shape.

Rose border. The cut involves a flat base and a dome of two or more rows of triangular facets, without forming a table. First appeared in India. The classic Indian version has 3 tiers and 24 sides of the dome. Currently on the market you can find several varieties of rose cut. For example, the Smolensk Gemological Center LLC developed a sixty-sided six-tiered variety of this cut with the trade name "Rose cabochon sixty-sided".

In addition to the usual types of fancy cuts discussed above, there are rare exclusive types. Such cuts, as already mentioned, are developed at a specific cutting enterprise, sometimes such a cut is performed by a single master. It also happens that one or another type of cut is developed at the request of the client for a certain product or for a certain stone - and then the cut exists in a single copy. Thus, one or another type of exclusive fancy cut will always be associated with a certain manufacturer or a certain product.

As an example of the range of exclusive fancy cuts, we can consider several cuts developed at the Smolensk Gemological Center LLC and manufactured at the Kristall Production Association OJSC: Zvezda cut BZ-41, Happy cut X-65, Phoenix cut ”, cut “Fiery rose sixty-one-sided” and others.

Technical requirements for fancy-cut diamonds are usually developed by each individual enterprise and presented in the form of flow charts. The technological map contains an image of a general view of a diamond of a certain cut in three (rarely two) projections and the main dimensions of the cut stone. The nomenclature of dimensional indicators will, of course, depend on the specific type of cut, but the main ones include: A - the total length of the cut stone; B - total width; α and β are respectively the angles of inclination of the crown and pavilion faces of the girdle plane; b p - the size of the area of ​​the diamond diameter in % of the diameter of the girdle; hr - girdle height in % of the diamond diameter. The card may contain requirements for different cut quality groups (A, B and C), then the quality group will be shown in the top line, as, for example, in Table.

Technological map for fancy shape diamonds "Oval" (on the example of Ov-57)

Group	Parameters of diamond A			B
n = A/B	1,20-1,80
Weight, s	up to 0.49	0,50-0,99	from 1.00	from 0.10
bр, %	55- 65	55- 65	55-65	55- 65
hr, %	1,5-3,0	0,7-2,5	0,7-2,5	0,7-3,0
α , deg.	30-35	30-35	30-36	30-36
β , deg.	39-42	39-42	39-42	39—42

Mixed cuts In the process of cutting stones, various combinations of the above types of both traditional and fancy types of mineral cutting are possible, that is, when the crown and pavilion are processed using different types of cutting (or processing). The most commonly used for colored stones are the brilliant cut of the crown and the fancy pavilion cut, or the crown and the pavilion are cut in various fancy cuts. An example of such a mixed cut is the Ceylon cut, which consists of a fancy cut crown (a modification from the full brilliant cut) and a checkerboard cut pavilion (a fancy variety of step cut). A mixed cut is possible, in which the crown is cut into a cabochon, and the pavilion is cut into a step cut.

Mixed cuts are widely used for colored transparent precious and semi-precious stones, such as almandines, heliodors, grossulars, rubies, sapphires, tourmalines, spinels, etc.

In ancient times, precious stones were considered a luxury. There were legends about them, as if each stone has an astrological significance and it has an energy field. For the people of that time, the cut of the stone and how it was combined with the setting was important. These stones were mentioned by writers in their books, artists depicted them in paintings. Some gems are witnesses of historical events.

Nowadays, gemstones should be carefully chosen. When buying a precious product, carefully inspect it, make sure that there is a sample and a reliable fastening of expensive stones. Expensive stones are beautiful and durable. There are about 4,000 types of gemstones. Their determining factors are color, brilliance, beauty and optical effects.

For example, gold earrings, like a dress, need to be tried on more than once. A small piece of jewelry looks much neater than a large piece of jewelry that catches the eye. And to everything else, the decoration should be not only beautiful, but also comfortable. Earrings with precious stones are always in fashion and serve as decoration, because, being close to the face, they will immediately attract the attention of others. But jewelry must match the eye color, face shape and age of the woman.

Gemstones photo and description

Classification of stones.

A diamond is the hardest stone in the entire universe. It is the most expensive gemstone, has a bright luster. They are evaluated according to the system: cut, clarity, color and carat weight. The largest diamond found in the world, the Cullinan, belongs to the British royal family and its largest pieces adorn the scepter and crown. This diamond was found in 1905 and weighed over 620 grams; Subsequently, when cutting, the diamond was divided into 9 large parts and 100 smaller ones. Its approximate price is equal to the price of 95 tons of pure gold.

Ruby is the second hardest gemstone after diamond. The color of a ruby ​​varies from light red to dark. The largest ruby ​​"Radja ratna" weighs 490 grams (2460 carats). A ruby ​​weighing up to 500 carats costs about $700,000.

Sapphire is most often bluish in color, although yellow, green, purple and pink sapphires are also found. It is a hard mineral suitable for jewelry. It occurs more often than ruby. It costs from $300 to $6,600 per carat.

Emerald. It has a green color due to impurities of iron, vanadium and chromium. Gems don't have this color anymore. The emerald is very fragile, but despite this, it is highly valued for its green color. The largest emerald weighing 25,000 carats has not been preserved, having split into many parts. The price of an emerald is from $900 to $27,000 per carat.

Agate has different color shades and shapes: there is green, white, gray, red, yellow and pink agate. This is a very famous stone, most commonly found in Brazil. Agate jewelry is diverse and looks very chic.

Aquamarine can be found green, blue and colorless. Its cost is low, as it is a common type of gemstone and ranges from $30 to $300 per carat. Aquamarine is a delicate stone suitable for girls who value their beauty and charm.

Alexandrite changes color from blue to green during the day, from pink to red in the evening. Wearing alexandrite is only paired with another alexandrite. This is a rather expensive gem - the price of alexandrite jewelry ranges from $6,000 to $32,000.

Amethyst is colorless, purple, blue and black. Violet amethysts are the highest standing, they are found in the Urals. They withstand high t and when heated to 250 ° C lose their color, but after cooling they return to color. The price of amethyst is from $4 to $40 per carat.

Turquoise is a beautiful blue, blue and green stone. The price of turquoise is $15 per carat and this stone is used as inserts in beads, rings, earrings and other jewelry. Turquoise is worn, as a rule, by smart girls, distinguished by their strict “royal” beauty.

Rhinestone. Touching the rock crystal, one feels cold. It is widely used due to its relatively low cost. The price of rock crystal is from $3 to $7 per carat. At the same time, rock crystal jewelry, which can be bought almost everywhere, looks very stylish, shimmering with iridescent colors.

Pomegranate is a mineral, outwardly similar to pomegranate grains, hence the name. There are different types: red, costing $ 13 - 48 per carat; demantoid, green, costing $35-90; spessartine, orange garnet; topazolite, yellow; pereneitis and melanitis - black garnet; leucogarnet, priceless. Garnet is not an expensive stone, but very beautiful.

Jadeite is a green mineral, but there are other shades. This stone is quite hard, but at the same time viscous - this allows you to create jewelry from jadeite of an original and unique form. Rarely found in nature, the price of jadeite ranges from $6 to $110 per carat.

Pearl. The mineral is round and irregular in shape. It comes in different colors: pink, white, red, black, yellow and others. The most valuable white and black pearls. An 8 mm pearl grows for about 40 years. This is a purely feminine jewelry, the cost of which is from $270 to $26,000.

Moonstone is a translucent silver spar. A very rare mineral, characterized by a mysterious pale bluish "lunar" color. And moonstone jewelry is worn by girls who want to highlight their mystery and mystery.

Nephrite is a hydroxide of iron, magnesium and calcium. It comes in yellow, grey, green, red and black. For the Chinese, it is a sacred stone. Its cost is 7 - 8 $. Jade jewelry can be bought quite a lot in a large number of stores, they are very common.

Opal can be red, blue, yellow, green and black. This is a fairly fragile stone. The largest opal was found in Brazil, weighing 22,000 carats and the price of this opal was $65,000. Opal is one of the most common stones in jewelry, enjoying great and well-deserved popularity.

Topaz is a semi-precious stone, aluminum fluorosilicate. It comes in gold, yellow, blue, pink, green and other colors. Has gloss and mother-of-pearl, it is difficult in processing. The largest topaz weighs 117 kilograms and was found in 1965 in Ukraine. The price of topaz is from $2 to $40 per carat.

Tourmaline is a type of boral aluminosilicate, a fairly fragile stone that has purple, pink, colorless, green, blue, brown and black hues. Its cost is from 60 to 800 $. Tourmaline jewelry is perfect for dresses for prom, weddings or other special occasions.

Citrine is a semi-precious stone, a variety of quartz. Transparent solid mineral, amber in color with a slight sheen, is not often found in nature. In jewelry, citrine rings are most often found, with a sunny hue that perfectly complements gold.

Amber is a mineral that contains carbon, hydrogen and oxygen. Its shades range from light yellow to golden. This is a fragile stone, crystalline structure, combustible. The cost of amber is $60..350 per kg. You can read more about it in one of our articles.

Remember, it changes from day to day. But this absolutely does not apply to precious stones, they are always appreciated. In the jewelry store you will find jewelry with any stone you are interested in. The main thing to remember is that when choosing a stone for yourself, you must feel it, this is perhaps the most important criterion in choosing jewelry.

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Along with gold and silver, precious and semi-precious stones have always been a symbol of wealth and power. It is customary to call precious minerals rare in nature, which have a beautiful appearance after cutting and polishing. They also emit semi-precious stones - these are minerals that are often found in nature, they are used to make both jewelry and various crafts.

Grade of raw materials

There are standards by which the quality of minerals is assessed and their price is set. This is the so-called grade of raw materials. The indicators for evaluation are:

• the degree of transparency of the mineral;
• color quality (uniform / clean / pronounced);
• interesting drawing;
• the absence (sometimes, on the contrary, the presence) of foreign particles, cracks;
• mineral size;
• strength / durability;
• the rarity of being in nature;
• fashion.

The fact that for one mineral is a minus, greatly underestimating its price, for another is a plus, increasing its value. For example, for a diamond, a contraindication is a foreign body inside or a crack. Whereas for amber, any of these factors can raise the value of the stone hundreds of times.

Therefore, speaking of precious stones, it is always necessary to specify the grade of the mineral and take into account its features. Both precious and ornamental stones have their own varieties and subspecies.

Definition of value

Each institution defines the concept of a precious stone in its own way. In the legal sense, this is a specific list of natural rocks: emeralds, diamonds, rubies, alexandrites, sapphires and pearls (all of natural origin). Thus, the state clearly defines a valuable natural resource, the turnover of which can be controlled.

Gemologists (specialists in minerals) define the concept of precious stones more broadly, linking the value of a stone with its main characteristics: hardness, transparency and rarity in nature.

Separate semi-precious and ornamental (non-precious) stones. The first type is the same minerals of natural origin, but inferior in quality to them. They can be opaque, break easily, often occur in nature, etc. Paradoxically, among semi-precious stones there are those that cost more than precious ones, for example, red spinel. Therefore, the assignment to the “sex” category is relative and it would be more accurate to call all of it “jewelry”.

Ornamental stones are mineral compounds most often used as mosaics, haberdashery, and applied arts.

There is no clear distinction between these three categories. In speech, they are often used as synonyms, sometimes mixing two groups into one (precious ornamental). In Russian, there is a good general concept for all minerals, depending on their characteristics - gems.

There are also several classifications of precious stones, although they are generally similar. Most of them are based on the division by cost and purpose.

Precious types of minerals

The most valuable among precious stones is considered a diamond, or in an uncut stage - a diamond. According to its chemical composition, it is a kind of carbon (or the lead of a simple pencil), it has amazing strength, and after cutting - beauty.

Classic Gemstone Composition:

All gems have one thing in common: a rarity in nature, a high degree of hardness and a bright interesting appearance after cutting. They never lose their value, even in wartime.

Semiprecious stones

In total, there are more than a hundred types of this type of stones. Their abundance in nature determines which semi-precious stones should be included here. Although all of them are natural, any one can be quite easily obtained, processed and embodied in the form of jewelry.

It is customary to refer to the main group of these stones:

Semi-precious stones are the most popular materials for jewelry and personal use.

Minerals of wide application

A separate group includes stones that are widely used in interiors, and not in the jewelry industry. They also have strong magical properties, they can be purchased or given as a decoration:

All of these stones have become famous through jewelry and handicrafts. Many luxurious interiors were decorated with natural minerals. For example, everyone has heard of the famous Amber Room, the malachite box.

Jewels in history

In all cultures and at all times, magical properties were attributed to natural minerals. Jade is a symbol of life. Amber helps with toothache. Jasper has always been revered in Japan, and turquoise - in Russia. Products from semi-precious stones are even more popular because they are available to a wide range of people.

No matter how fashion changes, there is always a place for jewelry. No matter what happens to the economy, and no matter what era comes, natural minerals never lose their value.

Precious stones are valued for their beauty, harmony of color and natural outlines, noble cut style. Thousands of years before our era, jewelry was found in nature, protected, decorated with clothes, jewelry, religious objects.

At the beginning of the twentieth century, it became possible to produce synthetic stones, in the photo they cannot be distinguished from real ones. Natural minerals are still valued more and cost accordingly.

Stones are divided into three groups:

• precious ones that jewelers use, they are also called gems;
• ornamental, from which decorative items are made - caskets, figurines, ashtrays;
• jewelry and ornamental, intermediate group.

There is no single classification, sometimes certain stones are attributed either to jewelry or to semi-precious ones.

Names, descriptions and classification

Precious gems in most countries are classified at the legislative level.

Precious minerals are determined by the beauty and purity of color, hardness, ability to maintain properties under mechanical stress. There is a general description, catalogs with photos.

Minerals are classified:

• genetically (by origin) and by chemical composition;
• on the basis of crystallography.

The first group of gems is divided into orders and the following names.

First order:

• - translucent, the shade varies from blue-green to pink-raspberry;
• - "indestructible", the hardest mineral. Precious gems are colorless, yellow, blue, red, black and blue;
• Emerald is a green and transparent gem. An ideal stone is valued more than a diamond;
• - red mineral, pink shade is allowed. It is also used in quantum electronics;
• Sapphire is a blue gem, in the old days it was called "baus".

Second order:

• - "sea water", a transparent, light blue stone;
• - a green mineral, very similar to jade;
• Opal - a stone with a beautiful iridescent overflow of white, red, blue, green colors;
• - it can be colorless, golden, pale blue, pink;
• Zircon - "golden", a description translated from Persian. Transparent stones are used by jewelers.

Third order:

• - a variety of quartz, it can be of any color;
• Turquoise is the stone of happiness. There is such a description - "victorious." Turquoise is famous for its characteristic blue-green color;
• Rock crystal - transparent and pure quartz, exquisite in the photo;
• - "similar to grains." Red, purple, green stone, which was also called "lal", opaque in the photo;
• - volcanic glass

Fourth order:

• - “not to be drunk”, a description translated from ancient Greek. Violet variety of quartz;
• it is green, colorless, black. The red varieties were called "lal";
• is a yellow variety of quartz.

Stones of organic origin are distinguished into a separate group:

• - a type of coal;
• Pearls - formation in the shell of a mollusk, is not a mineral. It happens white, blue, pink, black;
• represents the skeleton of a colony of polyps. It happens in red and pink, as well as silver (“angel skin”), white and black (“akkabar”);
• - fossilized resin. It is yellow, brown, colorless, greenish.

Belonging to one or another list is relative. According to some classifications, the same gems can be listed in different orders. There is also an industrial description.

The influence of stones on a person

Beautiful minerals are stored in banks and private collections (they can only be seen in the photo), especially rare specimens are exhibited in museums, they are complemented by jewelry and works of art.

They have always attracted humanity with their beauty and rarity. Currently, gems are used:

• in jewelry art;
• in lithotherapy (treatment);
• in magic, as well as in meditation and mystical practices.

Gems and jewelry art are connected by aesthetics, high artistic value of products. Men and women adorned themselves thousands of years ago with earrings, bracelets, beads, headdresses with minerals.

In lithotherapy, only natural natural minerals are used. Their application is quite wide:

• preparation of medicines;
• production of health massagers, rosaries, pyramids;
• energy charging of water;
• stimulation of biologically active points of the body;
• restoration of the movement of energies in the body;
• strengthening and cleansing the aura, charging the chakras;
• body toning.

Magical properties were also attributed to gems long before our era. They were used in divination, in the administration of various cults and in the manufacture of sacred objects. Minerals are very individual and personal, they adapt to the energy of the owner. Products are stored in caskets and boxes, away from the light, washed with clean water and wiped with soft tissues to remove negativity.

With the help of a talisman stone, you can:

• dispel negative energy in the house;
• attract love, wealth, success, prosperity, longevity;
• stimulate spiritual awakening and renewal;
• find harmony and peace of mind;
• get in touch with the astral world;
• protect yourself from evil, bad deeds, evil tongues, drunkenness;
• awaken wisdom and power of thought;
• attract patrons and friends;
• gain protection from fire and water, from the forces of the elements;
• cure ailments.

Many gems become the object of fakes. In order for the product to be useful, and not just pleasing to the eye, it must be completely natural, natural. Precious minerals are bought by referring to the photo in the directory and the descriptions of the properties.

Gems are an amazing and beautiful part of the planet Earth, a demonstration of the beauty of nature and matter. Minerals are always chosen, trusting intuition and taste, because the right choice helps to find not just an ornament, but also a talisman that will help improve the quality of material and spiritual life.