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Physical properties and photos of galena. Big encyclopedia of oil and gas

For more than one millennium, people have been smelting lead from galena. And in our time, this common mineral is its main industrial source. Pliny the Elder used the Latin word "galena" to name lead ore. Synonym: lead luster. Continuous dense fine-grained masses are sometimes called "pig".

Composition - lead sulfide (PbS). Refers to simple sulfides - minerals consisting of only one metal and sulfur. Typical impurities: silver, iron, gallium, germanium, titanium, selenium, bismuth. In nitric acid, it decomposes with the release of sulfur flakes and a white precipitate consisting of lead sulfate (PbSO4). In nature, this substance is found in the form of the mineral anglesite.

Usually galena forms continuous granular masses and disseminations; Occasionally, druse voids contain crystals of a cubic or octahedral shape. Sometimes spectacular "skeletal" twin crystals are found. Color: lead gray. Opaque. Luster: dull; strong metallic on the cleavage planes.

System: cubic. Cleavage is very perfect in three directions (along the edges of the cube): upon impact, it crumbles into small cubes and forms stepped ledges. Very fragile. Hardness: 2.5 - 3. Due to the high content of lead, it is very heavy: average specific gravity - 7.5 g / cm3. Trait: dark gray to black.

Galena in the breed. Photo: V. Popov.

Galena is a typical mineral of medium-temperature hydrothermal deposits, skarn. Sometimes it is part of sedimentary rocks. It usually occurs in close intergrowth with simple and complex sulfides: pyrrhotite. Other accompanying minerals: calcite, quartz, barite, fluorite, native gold; in skarns - as well as pyroxenes (augite, aegirine, enstatite, etc.).

It is unstable in oxidation zones: under the influence of oxygen, heat, sunlight, groundwater, it passes into cerussite and other secondary lead minerals. Their precipitates usually cover the galena surface with a brown (from iron impurities) powdery coating or grayish crusts, often partially or completely replacing it.

Galena is 87% lead and is the main source of lead. It is part of polymetallic ores. However, being a widespread mineral, it rarely forms large accumulations of industrial interest. The content of Ag impurities in galena averages only 0.1%. Nevertheless, galena accounts for a significant share of the world's silver production.

In Russia, it is mined in the Rudny Altai, in the Eastern Transbaikalia, in the North Caucasus. Magnificent crystals and twins up to 20 cm in size are found in the Nikolaevsky mine (Dalnegorsk, Primorsky Territory). Excellent samples come from the Czech Republic (Pribram), Bulgaria (Madan), Romania (Herge), Germany (Saxony-Anhalt), Mexico (Chihuahua). The world leader in the extraction of galena is the United States. Large crystals are found in the states of Wisconsin, Oklahoma, Missouri, Kansas. There are industrial deposits in Hungary, Australia, Peru, Canada.

In small grains, galena sometimes resembles native platinum, sphalerite, and also antimony sulfide, from which it differs in the shape of crystals, the nature of cleavage, and hardness. But the main diagnostic feature of galena is its severity.

Galena. Twin crystals. © Lou Perloff

For at least three millennia, galena has been used as a lead ore. Even in Ancient Egypt, coins were made from heavy metal. In ancient Rome, water pipes were made from it. Until the middle of the last century, lead was widely used in household items. It was added to gasoline; he found application in the printing industry, paint and varnish industry.

Nowadays, it is known that lead is toxic, therefore, whenever possible, it is replaced with harmless materials or components. But it still remains an indispensable metal in the production of batteries and other electrical equipment, in the defense industry. Lead is traditionally used as a weight in fishing gear.

Galena inclusions are sometimes present in,. The so-called "chipmunk ore" is used as an ornamental stone - granular sphalerite, interbedded with galena, chalcopyrite, magnetite. Galena can look very impressive, especially when combined with other minerals like sphalerite or quartz.

Galena on quartz (Dalnegorsk, Primorsky Territory). © Wendell Wilson

But under the influence of atmospheric agents, lead sulfide soon loses its metallic luster. To prevent samples from fading over time, it is recommended to keep them away from moisture and sunlight.

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The mineral galena, on the one hand, is necessary as a source of lead, and on the other hand, it is toxic. And as mankind has used this metal for thousands of years in various spheres of life, so now it is actively limiting its use. However, the lead mineral galena was created by nature, and the rationality and safety of its impact depends only on humans.

Galena is a toxic mineral

Description of galena

Galena is a lead sulfide with the chemical formula PbS. The composition may contain impurities of silver, cadmium, selenium, bismuth, iron, etc.

Galena properties:

  • crystal structure with cubic system;
  • low hardness (soft mineral) - 2.5-3;
  • very high density - 7.2-7.6 g / cm3. Due to the large amount of lead contained in galena (87%), the mineral is very heavy;
  • fragility;
  • fusibility;
  • steel, lead-gray in color with a bluish tint (see photo), sometimes with a reddish or blue tarnish (oxide film and light interference in it);
  • opacity;
  • dull metallic luster;
  • perfect cleavage (galena easily splits into cubic and stepped pieces);
  • solubility in nitric and hydrochloric acids.

The name of the mineral was given by Pliny the Elder (22 BC - 79 AD). From Latin galena means "lead ore". In another way, the stone is called gray ore, boleslavite, lead luster, plumbeyin.

Origin, formations, deposits

Galena is of magmatic origin. It is often found in intergrowth with other sulfides, as well as in close proximity to quartz, fluorite, garnets, pyroxenes, etc. Formations of galena have the form of cubic, cuboctahedral, octahedral (rarely) crystals and solid masses.

Mineral deposits are located in Russia, Mexico, Canada, USA, Australia, Germany, Czech Republic, Bulgaria, Italy, England.

Application history from antiquity to the present day

Even ancient peoples obtained lead from it. Thus, 8,400-year-old galena beads were found by archaeologists during excavations of the Neolithic settlement of Chatal Guyuk in southern Anatolia. The British Museum has an ancient Egyptian lead figurine of a woman in a long skirt, dated from 3,900 to 3,100. BC NS.

Even 3,000 years ago, the Romans smelted pipes from this metal, the Egyptians - medallions and coins. Galena, together with malachite, was used by ancient ladies even in decorative cosmetics - they received black eye paint from them. There is a mention of lead even in the Old Testament.

Ancient Rome at the time of its existence was the largest producer of lead (80 thousand tons per year). It was easy to mine and easy to handle. After the collapse of the empire in the 5th century, galena, like lead, ceased to be used so massively. In the 11th century, Germany resumed the use of the mineral, adding lead to wines to improve their taste.

There was little good in this, since such manipulations caused lead colic, and in 1498 the Pope banned them. In ancient Russia, churches were covered with galena melted into lead. In the 17th century, a water supply system was built from metal in the Kremlin, albeit not for long - until the first half of the 18th century. The early printers poured lead shapes and also added them to typographic alloys.

Lead became widespread, and with it galena as the main source of metal with the development of the industrial era. The metal began to be used in various fields:

  • in electrical engineering: cables, electrical fuses, batteries, etc.;
  • in the transport industry: antifriction alloys, antiknock agents in engines;
  • in the military industry: bullets, explosives;
  • in science: protective equipment against radioactive radiation;
  • in handicrafts and art products: lead glass, rhinestones with the addition of lead to obtain a greater shine. It used to be used by artists in paints and potters in glaze to cover pots;
  • in medicine: protective clothing in x-ray rooms;
  • in metallurgy.

By itself, galena stone is used:

  • in ceramics: galena is a flux (glass-forming agent);
  • to obtain silver: precious metal is extracted from the ore;
  • for the manufacture of modern nanomaterials (microprocessors, microchips, in which galena is able to speed up data transfer), semiconductor protective films;
  • as a material for photodetectors, semiconductor technology, infrared detectors.

However, due to the carcinogenic and teratogenic properties of lead (it causes deformations and deformities of the fetus even in the womb, and also slows down the development when it enters the child's body), since the year 2000, the entire civilized world has been actively reducing its use and is looking for an alternative to the material.

Jewelry and semi-precious stones

Galena Ore is not used in Jewelry Crafting. However, galena inclusions are rarely found in turquoise and beryl, giving them a special shine. Galena is included in the "chipmunk ore" (sphalerite, magnetite, galena, chalcopyrite), from which beautiful handicrafts are made. Galena makes the associations of different minerals such as quartz, sphalerite spectacular, which can be appreciated from photographs.

Thus, galena is one of the incredibly valuable, useful and at the same time harmful minerals in the world.

English name - Gаlеnite

origin of name

The Latin name of the mineral is galena - lead ore is mentioned by Pliny. The name galena was given by Kobel (1838).

Synonyms for the mineral galena:

Galena(Glocker, 1847). Apparently, mixtures of galena with other minerals are steinmannite (Tsipe, 1833), targionite (Behey, 1852), cuproplumbite (Breithaupt, 1844), johnstonite (Haidinger, 1845), alisonite (Field, 1859), furietite (Maine, 1860 ), guascolite (Dana, 1868), plumbocuprite and nolascite (Adam, 1869), paracobellite (Shrauf, 1871), kilmakuite (Tishborne, 1885).
Fine-grained masses of galena with a matte sheen are combined under the name pig. Quirogite from the Sierra Almagrera (Spain), described by Navaro (1895) as a tetragonal mineral, according to X-ray data, turned out to be a galena of a special, distorted appearance. Castillite was found to be a mixture of galena with Zn and Ag sulfides (Ramelsberg, 1866; Kalb, 1923). Richmondite (Skei, 1877) is a mixture of galena, fahlore, sphalerite and others. Plumbomangite (Köhlin, 1911) is a mixture of galena with various ore minerals.

An intergrowth of crystals with forms of uneven development on the faces and edges of the cube. Primorye Dalnegorskoye field

Chemical composition of galena

The theoretical chemical composition of the mineral: Pb - 86.60; S 13.40. S is isomorphically replaced by Se; there is a continuous isomorphic series of galena (PbS) - claustalite (PbSe), various representatives of which are found in nature. often contains an Ag impurity, usually up to 0.1%, less often 0.5-1% and more, which is partly due to the presence of inclusions of silver sulfides, partly to the presence of AgBiS 2 in the solid solution. Analyzes also show the presence of Zn, Cd, Sb, Bi, Cu, Sn, In, Tl, Au, Pt and others (usually no more than tenths of a percent); in most cases, this is due to the presence of impurities of other minerals: sphalerite, boulangerite, chalcopyrite and others.
Lead in galena is a mixture of isotopes Pb 204, Pb 206, Pb 207, and Pb 208. The last three isotopes in the earth's crust are continuously accumulating due to the radioactive decay of U and Th. The lead isotopic composition of galena can be used to determine the absolute age.


Varieties

Selenium galena of Ore Altai, containing a small amount of Se, and intermediate members of the galena-claustalite series from Colorado (USA), in which the PbSe content varies from 6.5 to 93.7 mol%. %. Altai selenium galena has a density of 7.2 - 7.5. Cleavage planes have a dull sheen, often tarnishing - from bronze-yellow to bluish-black. Unlike ordinary galena, it is less stable when weathering. Found in the Zyryanovsky and Chudak deposits in the form of veins among copper ores in association with chalcopyrite, pyrite, tetrahedrite. Galena-claustalites of the Colorado Plateau (USA) form disseminations in sulfide veinlets of uranium-vanadium deposits.

Svinchak - dense matte galena.

Crystallographic characteristic

The system is cubic, the class is hexaoctahedral

Crystal structure Face-centered cubic lattice with four molecules per unit cell.

The main forms are cubic, cuboctahedral, octahedral, rarely trioctahedral and hexoctahedral. Skeletal crystals of a cubic appearance are known. Unevenly developed crystals, elongated, columnar, elongated, and also tabular along the face of a cube or octahedron, are not uncommon.

Form of being in nature

Crystal appearance.


Crystals - from small to large (several centimeters in size) - are rarely ingrown, in most cases they grow and form druses and groups.

There are frequent twins of the mineral along (111), the most common are twins of accretion and germination, often tabular, sometimes polysynthetic; twin growths are observed according to (441), according to (311) and (331), causing oblique streakiness on the sides of the cube; twinned growths along (520) or (730) are indicated for galena from Ratibořice (Czech Republic), secondary twins of deformation according to (322), (221), (771) and (411). Forms oriented intergrowths with cotunnite, phosgenite and anglesite, pyrite, chalcopyrite, bournonite, fahlores, pyrrhotite, arsenopyrite, pyromorphite.

Aggregates.

The most common are grains and granular aggregates, less often - dense masses of drusen, sometimes - drip aggregates; crystals and crystalline skeletal formations are relatively common.

Physical properties
Optical

  • The color is lead-gray, somewhat lighter in fine-grained aggregates; galena with octahedral jointing, containing Bi, is somewhat darker; sometimes motley tarnishing is observed.
  • The line is grayish black.
  • Metallic luster, strong on cleavage planes; galena with octahedral jointing has a slightly dimmer luster; dense varieties are often dull.

Perfect cleavage in three directions

Mechanical

  • Hardness 2-3.
  • Density 7.4-7.6
  • The cleavage is perfect (along the cube), in three directions parallel to the sides of the cube (100).

Separation along (111) is sometimes observed, which is characteristic of galena with an increased bismuth content, which is explained by bismuthin inclusions located partly along (111) galena (the result of the decomposition of a solid solution of bismuth sulfide in galena) or the existence of a solid solution of AgBiS 2 in galena. When heated, the octahedral separation disappears and is replaced by cube cleavage.

The fracture of the mineral in dense masses is flat-shelllike, uneven; in galena with octahedral jointing, the fracture is finely stepped.

Galena. Chemical properties

The mineral in HNO 3 dissolves with the release of S and lead sulfate; from the nitric acid solution, upon addition of HCl, a white precipitate of PbCl 2, soluble in hot water, precipitates. Galena also decomposes with hot or strong HCl.
Solutions of NaCl, CaCl 2 have an effect on the mineral, especially at elevated temperatures and pressures.
In polished thin sections from HNO 3 it quickly turns black, from HCl it turns slightly brown, from FeCl 3 an iridescent tarnishing is formed; KCN, KOH, HgCl 2, (NH 4) 2 S is not etched. The structural features of the aggregates are revealed by etching with HCl (1: 1 or 1: 5). Microchemically, Pb is determined with KCN on a thin section, S - by the method of imprinting on silver bromine paper. Film reaction: with a saturated solution of J in 5% KJ, when boiling, the mineral turns yellow-green.

Other properties

Mineral conducts electricity. On the verge of the octahedron, the mineral has a higher electrical conductivity than on the verge of the cube. Electrical conductivity increases with increasing temperature, but drops sharply above 300 ° (Niggli). Detects either positive or negative photoelectric effect. Galena with a positive photoelectric effect has no detector properties; galena, which produces a negative photoelectric effect, are good detectors. Diamagnetic.

Mineral behavior when heated: Melting point. 1112 °. At high temperatures (above 350 °), PbS forms solid solutions with AgBiS 2. Ramdor (1955) explains the high content of Ag in galena, which does not contain microscopically detectable minerals - Ag carriers. It is characteristic that in these cases there is always a noticeable, often equivalent amount of Bi. Thus, in galena formed at medium and elevated temperatures, it can be assumed that Matildite is in a solid solution.

The stone is easily pricked by steps along three mutually perpendicular planes.

Getting galena

It is easily obtained in various ways (Dölter, 1925), for example, by the action of H 2 S on acidified HNO 3 solutions of Pb salts (amorphous and crystalline PbS); during the interaction of Pb chloride compounds with dry H 2 S in a heated tube; during the decomposition of lead sulfate in an atmosphere of H 2 or CO; when lead sulfate interacts with a rotting organic matter in water, when pyrite or marcasite is heated with a solution of PbCl 2.

Diagnostic signs

The mineral is easily identified by its color, gloss, characteristic cube cleavage, low hardness and high density. In fine-crystalline masses, it differs from similar antimony and arsenic compounds in density, behavior under a blowpipe and chemical reactions.
In polished thin sections, the possibility of mixing galena with other common white isotropic minerals is almost excluded, since it clearly differs from them in the main features: reflectivity, color, hardness, and especially in chipping triangles. In small grains it can be mixed with altaite (PbTe), claustalite (PbSe), but the former is significantly, and the latter is only slightly lighter and much softer.

Satellites. Its most typical companion among hypogenic minerals in various deposits is sphalerite - this is the so-called polymetallic ores. ; often accompanied by pyrite and chalcopyrite. The vein minerals in most hydrothermal deposits are quartz, barite, fluorite, and calcite.

Origin and location

Galena is one of the most common sulfide minerals in hydrothermal deposits, formed at different temperatures and in different geological settings. Medium and low temperature hydrothermal deposits are of the greatest industrial importance. In the form of small rare grains, the mineral is found in pegmatites of granite and alkaline magma, as a rare mineral in igneous rocks and volcanic deposits. Hypergene galena is found in some sedimentary formations. Sometimes the mineral forms almost monomineral ores (as, for example, in the Zavodinskoye deposit in Rudny Altai), usually it is accompanied by other sulfides.


Mineral change

It easily changes under natural conditions with the formation of cerussite, anglesite, pyromorphite, mimetesite, bedantite, less often linarite, plumboyarosite, massicot, wulfenite, phosgenite, cotunnite and other minerals. In galena pseudomorphs, the following are known: cerussite, anglesite, wulfenite, pyromorphite, calamine, limonite, tetrahedrite, chalcocite, rhodochrosite, quartz, pistomesite. Most commonly, galena is replaced by cerussite, sometimes with the release of native sulfur.

Place of Birth

In deposits among skarns in the contact zones of granitoids and sedimentary rocks (mainly limestones), galena forms dissemination and granular aggregates, sometimes found in significant quantities, accompanied by skarn minerals, sphalerite, chalcopyrite, pyrrhotite, etc. Examples: Altyn-Topkan in the Karamazar Mountains (Tajikistan ), Tetyukhe (Primorsky Territory), Kyzyl-Espe, Aksoran and Akchagyl (Northern Balkhash, Kazakhstan), Savinskoye and other deposits of the Chita region, Darwin (California, USA), Schwarzenberg (Saxony, Germany) and others.
In lead-zinc ores that form deposits and veins, galena, in close association with sphalerite, is accompanied by pyrite, chalcopyrite, often arsenopyrite, as well as fahlores, pyrargyrite, stephanite, bournonite, boulangerite, and other complex sulfides containing Cu, P ... Occasionally it is also accompanied by Ni sulfides and arsenides.


Typical hydrothermal, mainly medium-temperature deposits are: lead-zinc deposits of Rudny Altai (Kazakhstan and Altai Territory) - Ridderskoye, Zyryanovskoye, Zmeinogorskoye and others; Sadonskoe vein deposit (North Ossetia, Russia); deposits of the Mehmaninsky ore field (Azerbaijan); some deposits in the central part of Kazakhstan (Berkara, Maikain, Aleksandrovskoe, Kurgasyn, Azhim); deposits Achisay, Mirgalimsay; in the Karatau mountains (Kazakhstan); in the Chita region - deposits of the Nerchinsky district (Troitskoye, Smirnovskoye, Kadinskoye); vein deposits of Pribram (Czech Republic), Freiberg and Clausthal (Germany), Coeur d'Allen in the state. Idaho; Leadville in Colorado (USA), Salivan (Canada), Santa Eulalia (Mexico), Broken Hill and Mount Isa (Australia), Bodwin (Burma) and many others.


Relatively low-temperature deposits include the Bleyberg deposit (Austria), some deposits in Silesia (Poland), Rable (Northern Italy), and deposits of the "lead belt" of Missouri (USA).

In varying amounts, galena is also found in substantially copper deposits (in Russia - Dzhezkazgan, some pyrite deposits of the Urals), in deposits of sulfide-cassiterite formation (Yakutia, Primorsky Krai), in iron ore deposits (Bakalskoe deposit, Chelyabinsk region), in gold quartz veins (Berezovskoye deposit, Sverdlovsk region), in tungsten and molybdenum deposits (North-Kounradskoye, East-Kounradskoye, Karaobinskoye deposits of Kazakhstan).

Hypergene galena in sedimentary rocks occurs as a result of reduction by organic substances from lead sulfate or under the action of hydrogen sulfide on solutions of lead salts. Forms crusts and deposits on nodules of pyrite and marcasite, dissemination and thin films in coals (Borovichi district, Novgorod region). It occurs in limestones of various ages, in paragenesis with pyrite and marcasite, in the form of grains and crystals. In the Triassic deposits of Mount B. Bogdo (Astrakhan Region), galena was found as an interlayer in limestone. Occasionally observed in rocks of various Cambro-Silurian and Devonian horizons near St. Petersburg.
In cuprous sandstones and sandy limestones of the Cambrian age, galena is observed in the form of syngenetic dissemination (upper reaches of the Lena, Irkutsk oblast). In the Triassic ore-bearing variegated sandstones of the Kemern-Mechernich region (Germany), galena together with cerussite, chalcopyrite, and copper carbonates in the form of nodules and disseminated dissemination in sandstone is confined to a certain layer.

relatively widespread in phosphorite nodules of Podolia (Ukraine); it forms regular cubic crystals or makes irregular cavities inside the nodules, and is also located in their outer parts along the rays of the phosphate substance.

As a modern new formation, galena was noted in old mines: together with sphalerite in the form of deposits on iron chains in the mines of Upper Silesia (Poland), on abandoned tools - in crystals up to 12 mm in size in Missouri (USA).

There are known pseudomorphs of galena after cerussite, anglesite, pyromorphite, chalcocite, bournonite, fahlores, and wood.
Typomorphic properties of galena from hydrothermal deposits are, to some extent, the appearance of crystals and the content of impurities. Crystals of high-temperature hydrothermal galena are more often cubic in appearance, lower-temperature crystals are octahedral in appearance; high-temperature galena is often bismuth-bearing, while lower-temperature galena usually contains Ag and Sb.


Practical use

The most important lead mineral (almost all the world's production of Pb is associated with the extraction of galena). Along the way, silver, thallium, etc. are extracted from galena ores. In part, the ores are processed to obtain lead whitewash and glaze.

Physical research methods

Differential thermal analysis

Main lines on radiographs:

Ancient methods. It cracks and flies in pieces under a blowpipe on charcoal, and melts quietly in fine powder. Coal near the sample is covered with a yellow bloom of PbO with a bluish border (PbCO s). (Se-containing varieties form a reddish-brown coating with a narrow dark border on the coal near the sample; a characteristic, albeit weak, odor is found due to Se). With soda on charcoal, it produces a bead of Pb, which, after a prolonged blast, either completely disappears or, in the presence of Ag, leaves a small bead of Ag. Releases SO 2 in an open tube

Crystal-optical properties in thin preparations (thin sections)

Refractive indices 4.015 (C), 3.912 (D), 3.796 (F) (according to Vinchel).
In reflected light, white serves as a standard for white. Reflectivity (in%): for green rays 43.5, for orange - 37.5, for red - 35; according to Folinsby, measured with a photocell - 42.4. Isotropic. Sometimes it is anomalously anisotropic as a result of pressure or due to the presence of an isomorphic impurity α-AgBiS 2. Galena is polished well in fine-grained aggregates, worse in coarse-grained ones. A characteristic diagnostic feature is the presence of chipping triangles in polished thin sections, equally oriented within the limits of single-crystal grains; the reason for their formation is the perfect cleavage along the cube. Etching or weathering sometimes reveals a fine zonal structure, especially in low-temperature galena.

›Cerussite et al.

Galena- mineral, lead sulfide. inonyms: shine, boleslavite, plumbeyin, gray ore, lead shine.

Chemical composition- content (in%): Pb - 86.6; S 13.4; impurities of silver, selenium, bismuth, arsenic, antimony, copper, zinc are common.

Behavior in acids: dissolves in HNO3 with the release of sulfur and lead sulphate. Also decomposes in hot and strong HCl.

The mineral galena forms a series of solid solutions with clausthalite - PbSe.
Forms cubic, cuboctahedral, less often octahedral crystals and continuous coarse and fine-grained aggregates. Most often found in the form of granular and solid masses; forms drusen and skeletal crystals, as well as zonal reniform collomorphic masses with sphalerite. Epitaxic intergrowths with faded ores, arsenopyrite, bournonite, and native gold are known. Twin crystals, intergrowth and intergrowth twins are common. Sometimes it forms loose, mealy, cluster-shaped excretions mixed with sphalerite, called "cockade ore".
Deposits are hydrothermal (mostly medium and low temperature) and metasomatic. One of the most common hydrothermal sulphides, in association with sphalerite and chalcopyrite, is part of the so-called. polymetallic ores. Often forms rich clusters. It is characteristic that it is very often found in paragenesis with sphalerite, in relation to which it is usually found in subordinate quantities. Hydrothermal lead-zinc deposits are formed either as typical veins, irregular metasomatic deposits in limestones, or as phenocrysts. Sometimes it forms almost monomineral ores (for example, in the Zavodinskoye deposit, Rudny Altai). During oxidation in the process of weathering of hydrothermal deposits, galena is covered with a crust of anglesite, which passes from the surface into cerussite. These poorly soluble secondary minerals form, as it were, a dense jacket around the central sections of galena, not affected by destruction, stopping the access of oxidizing agents inside. Therefore, it is not surprising that solid masses of galena in the form of nodules with such a jacket are found in the zone of accumulation of clay deposits and even in placers. In contrast to sphalerite, due to galena in the oxidation zone, in addition to anglesite and cerussite, a number of other hardly soluble oxygen compounds arise: phosphates, arsenates, vanadates, molybdates, etc. As a result, the oxidation zones of lead-zinc deposits are usually enriched in lead.
It is also known in cryolite pegmatites and in zones of contact metamorphism. In addition, it can be found in limestones, in veins and veins, or filling voids. Under hypergene conditions, it changes with the formation of lead carbonates and sulfates. Sometimes it also occurs as a sedimentary-diagenetic formation, standing out in the form of disseminated dissemination in sandstones, limestones, as well as in the cores of nodules. The modern formation of galena from underground brines and mine waters has been established.
Location
Deposits are numerous throughout the world. In Russia, the largest galena deposits are known in Altai, the North Caucasus (Sadonskoe vein), Transbaikalia (Nerchinskoe), in Eastern Siberia and Primorye (Dalnegorskoe ore field); abroad - in Kazakhstan and Central Asia (Karamazar Mountains, etc.), in the Czech Republic (Pribram), Bulgaria (Madan), Romania (Herzhe), USA, Canada, Australia, African countries. Rich deposits in the United States are scattered mineralization, they are located in three states - Missouri, Oklahoma, Kansas; this area is called Three-Stayt ("three states") with the famous center of Joplin. The Australian (Broken Hill), English (Cumberland), Mexican (Chihuahua, Eulalia) and German (Andreasberg and Freiberg) deposits are also widely known. In Italy, for many centuries the deposits of Ryble (Carnic Alps), Gornaya Dossena (foothills of the Alps in Lombardy), Monteponi and Montevecchio (Sardinia) have been developed.
Practical value
Galena is the main ore for lead production. Along the way, valuable impurities always contained in it are extracted from it. Silver is recovered from some of the silver-containing galena as a by-product. The main share of silver and cadmium mining falls precisely on the share of polymetallic ores.

Mineral properties

  • Origin of name: named by Pliny the Elder in 77 - 79 AD in Greek galena - lead ore
  • Mineral electrical properties: Diamagnetic, conductor of electricity. Detects either positive or negative photoelectric effect. Galena with a negative photoelectric effect has detector properties.
  • Thermal properties: P. tr. on coal in pieces it cracks and scatters, in a fine powder it calmly melts, giving a bead of lead. Coal near the sample is covered with a yellow PbO bloom with a bluish border (PbCO3).
  • Luminescence: No
  • IMA status: valid, described for the first time before 1959 (before IMA)
  • Typical impurities: Ag, Cu, Fe, Bi
  • Strunz (8th edition): 2 / C.15-40
  • Hey "s CIM Ref .: 3.6.5
  • Dana (8th edition): 2.8.1.1
  • Molecular weight: 239.27
  • Cell parameters: a = 5.936Å
  • The number of formula units (Z): 4
  • Unit cell volume: V 209.16 ų
  • Twinning: According to the spinel law according to (111); polysynthetic twinning according to (114)
  • Point group: m3m (4 / m 3 2 / m) - Hexoctahedral
  • Space group: Fm3m (F4 / m 3 2 / m)
  • Separation: by (111)
  • Density (calculated): 7.57
  • Density (measured): 7.58
  • Type of: isotropic
  • Reflected light color: White
  • Allocation form: Typical are cubic crystals with (100), (111), and less frequently (110) faces. Developed twins along (111), hexahedrons, octahedrons, combinations of a cube with an octahedron, solid masses
  • Classes on the taxonomy of the USSR: Sulphides
  • IMA classes: Sulphides
  • Chemical formula: PbS
  • Systema: cubic
  • Colour: bluish gray, sometimes with dull tarnishing
  • Feature color: lead gray
  • Shine: metallic dull
  • Transparency: opaque
  • Cleavage: perfect by (001)
  • Kink: concave uneven
  • Hardness: 2,5 3
  • Microhardness: VHN100 = 79 - 104 kg / mm2
  • Fragility: Yes
  • Literature: Zhabin A.G. Coralite skeletons of galena with spherulite crusts of sphalerite from the Kadaya deposit (Eastern Transbaikalia). ZVMO, No. 1, 1994 Chesnokov B.V., Bushmakin A.F., Aronskind V.P. Galena with octahedral jointing from sulfide-quartz veins of the Berezovskoye deposit in the Sverdny Urals. Mineralogy and petrography of the Urals, vol. 1. Sverdlovsk: UPI, 1978. S. 42-48.

Mineral photo


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    Galena differs from arsenopyrite in color, low hardness, cubic cleavage and high density

Deposits of the mineral Galena

  • Dalnegorsk
  • Nikolaevsky mine
  • 2nd Soviet mine
  • Russia
  • Primorsky Krai
  • Amurskaya Oblast
  • Kola Peninsula
  • Tersky coast
  • Murmansk region
  • Berezitovoe
  • Tyndinsky
  • Krasnoyarsk region
  • Michigan
  • Detroit salt mine

The mineral galena belongs to lead sulfides and is the main source of its extraction. It is not surprising that its name is translated from Greek as "lead ore". It looks like fused opaque bluish-gray crystals of an interesting geometric shape: cubes, octahedrons and rhombododecahedrons.

The mineral has a characteristic metallic luster on the chips. It is very fragile and easily crumbles, as it has a very low hardness, about 2-3 units on the Mohs scale, while its density is quite high, it fluctuates in the range of 7.2 - 7.6 g / cm³. Obsolete names for galena: johnstonite, paracobelite, or potter ore. One of the varieties with increased density is called the lead.

Place of Birth

Galena is quite common throughout the world, but is rare in large quantities. Its deposits have been discovered in different countries of the world: Chile, Mexico, USA, Australia, Canada. The main Russian deposits are located in Altai, the North Caucasus, Primorye, Transbaikalia and Eastern Siberia. These are mainly hydrothermal deposits, but sometimes the mineral is found in sedimentary rocks. The most common neighbors are sphalerite, pyrite, quartz, calcite, dolomite and even native silver. Galena consists of more than 80% lead, but sometimes silver impurities are found in it.

Healing properties

It is believed that galena has the ability to tone the nervous system. To do this, use a tincture: the stone is placed on the bottom of the vessel and filled with water. Drinking is charged with the energy of the mineral and gives a person vigor, cheerfulness, physical activity, and also saves from drowsiness. Galena jewelry was credited with the ability to relieve depression.

According to ancient beliefs, galena gave a woman strength and helped during pregnancy. But modern science refutes this: lead compounds are very toxic and tend to accumulate in the body. It is unlikely that this will be useful when carrying a fetus. It is believed that galena reduces the desire for destructive habits in a person: smoking, drinking alcohol and drugs, as well as overeating and cravings for sweets.

Magical properties

There is an opinion that the galena mineral is able to strengthen the vitality of its owner, help achieve his goals, and help overcome various obstacles along the way. It is possible that this is due to the property described above to restrain bad habits and direct its owner to a healthy lifestyle. There is also a belief that the stone is able to attract fame to its owner, while he is able to protect him from star fever.

But it is not enough just to wear jewelry made of this mineral. The owner's indifference to galena can cause the stone to stop helping him. Therefore, it is recommended to regularly express your admiration for him, communicate with him. As a result of such meditative communication, the stone begins to feel the owner, reads out his aspirations and creates favorable conditions for their realization.

Signs of the zodiac

As for the astrological aspect, of all the signs of the zodiac, galena is most favored by Taurus, but it can be worn by everyone except Scorpio. Representatives of this sign are overly proud and arrogant, and galena does not like this, therefore, most often it is just an ornament for them. It is recommended to wear this stone to representatives of the humanities and creative people - for them it will be a good talisman.

Application of galena

First of all, it is the main source for lead mining. The smelting of this metal all over the world is associated precisely with the extraction of galena. Part of it is processed in order to obtain such preparations from lead as whitewash, red lead, glaze. If the ore contains silver impurities, then silver is also mined along the way.