Sphalerite is a
sulfide mineral 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. 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,
chalcopyrite,
pyrite (and other
sulfides),
calcite,
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, and
fluorite.
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,
gallium,
germanium, and
indium. Miners have been known to refer to sphalerite as ''zinc blende'', ''black-jack'', and ''
ruby blende''.
Marmatite is an opaque black variety with a high iron content.
Crystal habit and structure

Sphalerite crystallizes in the
face-centered cubic zincblende crystal structure,
which was named after the mineral. This structure is a member of the hextetrahedral crystal class (
space group ''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 polymorph of sphalerite is
wurtzite, 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](_blank)
ICCD reference 04-004-3804. Sphalerite has been found as a
pseudomorph, taking the crystal structure of
galena,
tetrahedrite,
barite and
calcite.
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
cadmium,
mercury and
manganese, but
gallium,
germanium and
indium 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 and
tellurium.
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, 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.
[
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 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 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 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 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 and christophite is named for the St. Christoph mine in Breitenbrunn, Saxony. Both marmatite and cleiophane are not recognized by the International Mineralogical Association (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.
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 and failed continental rifts. The main ore minerals in SEDEX deposits are sphalerite, galena, pyrite, pyrrhotite 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
Mount Isa ( ) is a city in the Gulf Country region of Queensland, Australia. It came into existence because of the vast mineral deposits found in the area. Mount Isa Mines (MIM) is one of the most productive mines in world history, based on co ...
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 ...
in 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
Yule Marble is a marble of metamorphosed Leadville Limestone found only in the Yule Creek Valley, in the West Elk Mountains of Colorado, southeast of the town of Marble, Colorado.Marble Quadrangle, Colorado; USGS 7.5-minute series topogr ...
– 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 ...
See also
* List of minerals
This is a list of minerals which have Wikipedia articles.
Minerals are distinguished by various chemical and physical properties. Differences in chemical composition and crystal structure distinguish the various ''species''. Within a mineral speci ...
References
Further reading
*Dana's Manual of Mineralogy
*Webster, R., Read, P. G. (Ed.) (2000). ''Gems: Their sources, descriptions and identification'' (5th ed.), p. 386. Butterworth-Heinemann, Great Britain.
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