Sphalerite is a

sulfide mineral The sulfide minerals are a class of minerals containing sulfide (S2−) or disulfide () as the major anion. Some sulfide minerals are economically important as metal ores. The sulfide class also includes the selenide mineral, selenides, the tell ...

with the

chemical formula A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as pare ...

. It is the most important ore of

zinc Zinc is a chemical element; it has symbol Zn and atomic number 30. It is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic tabl ...

. Sphalerite is found in a variety of deposit types, but it is primarily in sedimentary exhalative, Mississippi-Valley type, and volcanogenic massive sulfide deposits. It is found in association with

galena Galena, also called lead glance, is the natural mineral form of lead(II) sulfide (PbS). It is the most important ore of lead and an important source of silver. Galena is one of the most abundant and widely distributed sulfide minerals. It crysta ...

chalcopyrite Chalcopyrite ( ) is a copper iron sulfide mineral and the most abundant copper ore mineral. It has the chemical formula CuFeS2 and crystallizes in the tetragonal system. It has a brassy to golden yellow color and a Mohs scale, hardness of 3.5 to 4 ...

pyrite The mineral pyrite ( ), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Fe S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic luster and pale brass-yellow hue ...

(and other

sulfides Sulfide (also sulphide in British English) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to large families of ...

calcite Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...

, dolomite,

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...

rhodochrosite Rhodochrosite is a manganese carbonate mineral with chemical composition Manganese(II) carbonate, MnCO3. In its pure form (rare), it is typically a rose-red colour, but it can also be shades of pink to pale brown. It Streak (mineralogy), streak ...

, and

fluorite Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF2. It belongs to the halide minerals. It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncommon. The Mohs scal ...

. German geologist Ernst Friedrich Glocker discovered sphalerite in 1847, naming it based on the Greek word ''sphaleros'', meaning "deceiving", due to the difficulty of identifying the mineral. In addition to zinc, sphalerite is an ore of

cadmium Cadmium is a chemical element; it has chemical symbol, symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12 element, group 12, zinc and mercury (element), mercury. Like z ...

gallium Gallium is a chemical element; it has Chemical symbol, symbol Ga and atomic number 31. Discovered by the French chemist Paul-Émile Lecoq de Boisbaudran in 1875, elemental gallium is a soft, silvery metal at standard temperature and pressure. ...

germanium Germanium is a chemical element; it has Symbol (chemistry), symbol Ge and atomic number 32. It is lustrous, hard-brittle, grayish-white and similar in appearance to silicon. It is a metalloid or a nonmetal in the carbon group that is chemically ...

, and

indium Indium is a chemical element; it has Symbol (chemistry), symbol In and atomic number 49. It is a silvery-white post-transition metal and one of the softest elements. Chemically, indium is similar to gallium and thallium, and its properties are la ...

. Miners have been known to refer to sphalerite as ''zinc blende'', ''black-jack'', and ''

ruby blende Ruby blende or garnete blende are two close trivial names for several dissimilar minerals,''Krivovichev V. G.'' Mineralogical glossary. Scientific editor . — St.Petersburg: St.Petersburg Univ. Publ. House. 2009. 556 p. — ISBN 978-5-288-04863- ...

''. Marmatite is an opaque black variety with a high iron content.

Crystal habit and structure

Sphalerite-unit-cell-depth-fade-3D-balls

Sphalerite crystallizes in the

face-centered cubic In crystallography, the cubic (or isometric) crystal system is a crystal system where the unit cell is in the shape of a cube. This is one of the most common and simplest shapes found in crystals and minerals. There are three main varieties o ...

zincblende crystal structure, which was named after the mineral. This structure is a member of the hextetrahedral crystal class (

space group In mathematics, physics and chemistry, a space group is the symmetry group of a repeating pattern in space, usually in three dimensions. The elements of a space group (its symmetry operations) are the rigid transformations of the pattern that ...

''F''3m). In the crystal structure, both the sulfur and the zinc or iron ions occupy the points of a face-centered cubic lattice, with the two lattices displaced from each other such that the zinc and iron are tetrahedrally coordinated to the sulfur ions, and ''vice versa''. Minerals similar to sphalerite include those in the sphalerite group, consisting of sphalerite, colaradoite, hawleyite, metacinnabar, stilleite and tiemannite. The structure is closely related to the structure of

diamond Diamond is a Allotropes of carbon, solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Diamond is tasteless, odourless, strong, brittle solid, colourless in pure form, a poor conductor of e ...

. The

hexagonal In geometry, a hexagon (from Greek , , meaning "six", and , , meaning "corner, angle") is a six-sided polygon. The total of the internal angles of any simple (non-self-intersecting) hexagon is 720°. Regular hexagon A regular hexagon is d ...

polymorph of sphalerite is

wurtzite Wurtzite is a zinc and iron sulfide mineral with the chemical formula , a less frequently encountered Polymorphism (materials science), structural polymorph form of sphalerite. The iron content is variable up to eight percent.Palache, Charles, H ...

, and the trigonal polymorph is matraite. Wurtzite is the higher temperature polymorph, stable at temperatures above . The lattice constant for zinc sulfide in the zinc blende crystal structure is 0.541 nm.International Centre for Diffraction Data reference 04-004-3804
ICCD reference 04-004-3804. Sphalerite has been found as a pseudomorph, taking the crystal structure of

, tetrahedrite, barite and

. Sphalerite can have Spinel Law twins, where the twin axis is 11 The chemical formula of sphalerite is ; the iron content generally increases with increasing formation temperature and can reach up to 40%. The material can be considered a ternary compound between the binary endpoints ZnS and FeS with composition Zn_xFe_(1-x)S, where x can range from 1 (pure ZnS) to 0.6. All natural sphalerite contains concentrations of various impurities, which generally substitute for zinc in the cation position in the lattice; the most common cation impurities are

, mercury and

manganese Manganese is a chemical element; it has Symbol (chemistry), symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese was first isolated in the 1770s. It is a transition m ...

, but

and

may also be present in relatively high concentrations (hundreds to thousands of ppm). Cadmium can replace up to 1% of zinc and manganese is generally found in sphalerite with high iron abundances. Sulfur in the anion position can be substituted for by

selenium Selenium is a chemical element; it has symbol (chemistry), symbol Se and atomic number 34. It has various physical appearances, including a brick-red powder, a vitreous black solid, and a grey metallic-looking form. It seldom occurs in this elem ...

and

tellurium Tellurium is a chemical element; it has symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur, all three of which are chalcogens. It is occasionally fou ...

. The abundances of these impurities are controlled by the conditions under which the sphalerite formed; formation temperature, pressure, element availability and fluid composition are important controls.

Properties

Physical properties

Sphalerite possesses perfect dodecahedral

cleavage Cleavage may refer to: Science * Cleavage (crystal), the way in which a crystal or mineral tends to split * Cleavage (embryo), the division of cells in an early embryo * Cleavage (geology), foliation of rock perpendicular to stress, a result of ...

, having six cleavage planes. In pure form, it is a semiconductor, but transitions to a conductor as the iron content increases. It has a hardness of 3.5 to 4 on the

Mohs scale of mineral hardness The Mohs scale ( ) of mineral hardness is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of minerals through the ability of harder material to scratch softer material. The scale was introduced in 1812 by the Ger ...

. It can be distinguished from similar minerals by its perfect cleavage, its distinctive resinous luster, and the reddish-brown streak of the darker varieties.

Optical properties

Pure

zinc sulfide Zinc sulfide (or zinc sulphide) is an inorganic compound with the chemical formula of ZnS. This is the main form of zinc found in nature, where it mainly occurs as the mineral sphalerite. Although this mineral is usually black because of various i ...

is a wide-bandgap semiconductor, with bandgap of about 3.54 electron volts, which makes the pure material transparent in the visible spectrum. Increasing iron content will make the material opaque, while various impurities can give the crystal a variety of colors.Hobart M. King
Sphalerite
geology.com. Retrieved 22 Feb. 2022. In thin section, sphalerite exhibits very high positive

relief Relief is a sculpture, sculptural method in which the sculpted pieces remain attached to a solid background of the same material. The term ''wikt:relief, relief'' is from the Latin verb , to raise (). To create a sculpture in relief is to give ...

and appears colorless to pale yellow or brown, with no pleochroism. The

refractive index In optics, the refractive index (or refraction index) of an optical medium is the ratio of the apparent speed of light in the air or vacuum to the speed in the medium. The refractive index determines how much the path of light is bent, or refrac ...

of sphalerite (as measured via sodium light, average wavelength 589.3 nm) ranges from 2.37 when it is pure ZnS to 2.50 when there is 40% iron content. Sphalerite is isotropic under cross-polarized light, however sphalerite can experience

birefringence Birefringence, also called double refraction, is the optical property of a material having a refractive index that depends on the polarization and propagation direction of light. These optically anisotropic materials are described as birefrin ...

if intergrown with its polymorph wurtzite; the birefringence can increase from 0 (0% wurtzite) up to 0.022 (100% wurtzite). Depending on the impurities, sphalerite will

fluoresce Fluorescence is one of two kinds of photoluminescence, the emission of light by a substance that has absorbed light or other electromagnetic radiation. When exposed to ultraviolet radiation, many substances will glow (fluoresce) with color ...

under ultraviolet light. Sphalerite can be triboluminescent. Sphalerite has a characteristic triboluminescence of yellow-orange. Typically, specimens cut into end-slabs are ideal for displaying this property.

Varieties

Gemmy, colorless to pale green sphalerite from Franklin, New Jersey (see Franklin Furnace), are highly fluorescent orange and/or blue under longwave ultraviolet light and are known as ''cleiophane'', an almost pure ZnS variety. Cleiophane contains less than 0.1% of iron in the sphalerite crystal structure. Marmatite or christophite is an opaque black variety of sphalerite and its coloring is due to high quantities of iron, which can reach up to 25%; marmatite is named after Marmato mining district in

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

and christophite is named for the St. Christoph mine in Breitenbrunn,

Saxony Saxony, officially the Free State of Saxony, is a landlocked state of Germany, bordering the states of Brandenburg, Saxony-Anhalt, Thuringia, and Bavaria, as well as the countries of Poland and the Czech Republic. Its capital is Dresden, and ...

. Both marmatite and cleiophane are not recognized by the

International Mineralogical Association Founded in 1958, the International Mineralogical Association (IMA) is an international group of 40 national societies. The goal is to promote the science of mineralogy and to standardize the nomenclature of the 5000 plus known mineral species. ...

(IMA). Red, orange or brownish-red sphalerite is termed ruby blende or ruby zinc, whereas dark colored sphalerite is termed black-jack.

Deposit types

Sphalerite is amongst the most common sulfide minerals, and it is found worldwide and in a variety of deposit types. The reason for the wide distribution of sphalerite is that it appears in many types of deposits; it is found in skarns, hydrothermal deposits, sedimentary beds, volcanogenic massive sulfide deposits (VMS), Mississippi-valley type deposits (MVT),

granite Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...

and

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other Chemical element, elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal i ...

Sedimentary exhalitive

Approximately 50% of zinc (from sphalerite) and lead comes from Sedimentary exhalative (SEDEX) deposits, which are stratiform Pb-Zn sulfides that form at seafloor vents. The metals precipitate from hydrothermal fluids and are hosted by shales, carbonates and organic-rich siltstones in

back-arc basins A back-arc basin is a type of geologic Structural basin, basin, found at some convergent boundary, convergent plate boundaries. Presently all back-arc basins are submarine features associated with island arcs and subduction zones, with many found ...

and failed continental rifts. The main ore minerals in SEDEX deposits are sphalerite, galena, pyrite,

pyrrhotite Pyrrhotite (''Pyrrhus of Epirus, pyrrhos'' in Greek language, Greek meaning "flame-coloured"'')'' is an iron sulfide mineral with the formula Fe(1−x)S (x = 0 to 0.125). It is a nonstoichiometric compound, nonstoichiometric variant of FeS, th ...

and marcasite, with minor sulfosalts such as tetrahedrite- freibergite and boulangerite; the zinc + lead grade typically ranges between 10 and 20%. Important SEDEX mines are Red Dog in

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

, Sullivan Mine in

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

, Mount Isa and

Broken Hill Broken Hill is a city in the Far West (New South Wales), far west region of outback New South Wales, Australia. An inland mining city, it is near the border with South Australia on the crossing of the Barrier Highway (A32) and the Silver City Hi ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

and Mehdiabad in

Iran Iran, officially the Islamic Republic of Iran (IRI) and also known as Persia, is a country in West Asia. It borders Iraq to the west, Turkey, Azerbaijan, and Armenia to the northwest, the Caspian Sea to the north, Turkmenistan to the nort ...

Mississippi-Valley type

Similar to SEDEX, Mississippi-Valley type (MVT) deposits are also a Pb-Zn deposit which contains sphalerite. However, they only account for 15–20% of zinc and lead, are 25% smaller in tonnage than SEDEX deposits and have lower grades of 5–10% Pb + Zn. MVT deposits form from the replacement of carbonate host rocks such as dolostone and limestone by ore minerals; they are located in platforms and foreland thrust belts. Furthermore, they are stratabound, typically Phanerozoic in age and epigenetic (form after the lithification of the carbonate host rocks). The ore minerals are the same as SEDEX deposits: sphalerite, galena, pyrite, pyrrhotite and marcasite, with minor sulfosalts. Mines that contain MVT deposits include Polaris in the Canadian arctic, Mississippi River in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

, Pine Point in Northwest Territories, and Admiral Bay in Australia.

Volcanogenic massive sulfide

Volcanogenic massive sulfide (VMS) deposits can be Cu-Zn- or Zn-Pb-Cu-rich, and accounts for 25% of Zn in reserves. There are various types of VMS deposits with a range of regional contexts and host rock compositions; a common characteristic is that they are all hosted by submarine volcanic rocks. They form from metals such as copper and zinc being transferred by hydrothermal fluids (modified seawater) which leach them from volcanic rocks in the oceanic crust; the metal-saturated fluid rises through fractures and faults to the surface, where it cools and deposits the metals as a VMS deposit. The most abundant ore minerals are pyrite, chalcopyrite, sphalerite and pyrrhotite. Mines that contain VMS deposits include Kidd Creek in Ontario, Urals in

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

, Troodos in

Cyprus Cyprus (), officially the Republic of Cyprus, is an island country in the eastern Mediterranean Sea. Situated in West Asia, its cultural identity and geopolitical orientation are overwhelmingly Southeast European. Cyprus is the List of isl ...

, and Besshi in

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

Localities

The top producers of sphalerite include the United States, Russia,

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

, Australia,

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

Ireland Ireland (, ; ; Ulster Scots dialect, Ulster-Scots: ) is an island in the North Atlantic Ocean, in Northwestern Europe. Geopolitically, the island is divided between the Republic of Ireland (officially Names of the Irish state, named Irelan ...

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

Kazakhstan Kazakhstan, officially the Republic of Kazakhstan, is a landlocked country primarily in Central Asia, with a European Kazakhstan, small portion in Eastern Europe. It borders Russia to the Kazakhstan–Russia border, north and west, China to th ...

and

England England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It ...

. Sources of high quality crystals include:

Uses

Metal ore

Sphalerite is an important ore of zinc; around 95% of all primary zinc is extracted from sphalerite ore. However, due to its variable trace element content, sphalerite is also an important source of several other metals such as cadmium, gallium, germanium, and indium which replace zinc. The ore was originally called ''blende'' by miners (from German ''blind'' or ''deceiving'') because it resembles galena but yields no lead.

Brass and bronze

The zinc in sphalerite is used to produce

brass Brass is an alloy of copper and zinc, in proportions which can be varied to achieve different colours and mechanical, electrical, acoustic and chemical properties, but copper typically has the larger proportion, generally copper and zinc. I ...

, an alloy of copper with 3–45% zinc. Major element alloy compositions of brass objects provide evidence that sphalerite was being used to produce brass by the Islamic as far back as the

medieval ages In the history of Europe, the Middle Ages or medieval period lasted approximately from the 5th to the late 15th centuries, similarly to the post-classical period of global history. It began with the fall of the Western Roman Empire and ...

between the 7th and 16th century CE. Sphalerite may have also been used during the cementation process of brass in Northern China during the 12th–13th century CE ( Jin Dynasty). Besides brass, the zinc in sphalerite can also be used to produce certain types of bronze; bronze is dominantly copper which is alloyed with other metals such as tin, zinc, lead, nickel, iron and arsenic.

Other

* Yule Marble – sphalerite is found as inclusions in yule marble, which is used as a building material for the

Lincoln Memorial The Lincoln Memorial is a List of national memorials of the United States, U.S. national memorial honoring Abraham Lincoln, the List of presidents of the United States, 16th president of the United States, located on the western end of the Nati ...

and Tomb of the Unknown. * Galvanized iron – zinc from sphalerite is used as a protective coating to prevent corrosion and rusting; it is used on power transmission towers, nails and automobiles. * Batteries. *

Gemstone A gemstone (also called a fine gem, jewel, precious stone, semiprecious stone, or simply gem) is a piece of mineral crystal which, when cut or polished, is used to make jewellery, jewelry or other adornments. Certain Rock (geology), rocks (such ...

Gallery

File:Sphalerite-barite (Cumberland Mine, Smith County, Tennessee, USA).jpg, Sphalerite and barite from Cumberland Mine, Tennessee, US File:Sphalerite on dolostone (Millersville Quarry, Sandusky County, Ohio, USA).jpg, Sphalerite on dolostone, from Millersville Quarry, Ohio, US File:Calcite-Sphalerite-elm05b.jpg, Tan crystal of calcite attached to a cluster of black sphalerite crystals File:Sphalerite-221270.jpg, Sharp, tetrahedral sphalerite crystals with minor associated chalcopyrite from the Idarado Mine, Telluride, Ouray District, Colorado, US File:Sphalerite-Quartz-261762.jpg, Gem quality twinned cherry-red sphalerite crystal (1.8 cm) from Hunan Province, China File:Esfalerita (Blenda acaramelada) Áliva, Cantabria.jpg, Sphalerite crystals from Áliva, Camaleño, Cantabria (Spain) File:Fluorite and sphalerite J1.jpg, Purple fluorite and sphalerite, from the Elmwood mine, Smith county, Tennessee, US File:Geodized brachiopod.jpg, Sphalerite crystal in geodized

brachiopod Brachiopods (), phylum (biology), phylum Brachiopoda, are a phylum of animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear e ...

References

External links

The sphalerite structure
* ttp://www.minerals.net/mineral/sulfides/sphaleri/sphaleri.htm Minerals.netbr>Minerals of Franklin, NJ
{{Authority control Gemstones Sulfide minerals Zinc minerals Cubic minerals Minerals in space group 216 Luminescent minerals Zincblende crystal structure Minerals described in 1847 Blendes