Sphalerite

Sphalerite

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Sphalerite is a mineral
Mineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...

 that is the chief ore
Ore
An ore is a type of rock that contains minerals with important elements including metals. The ores are extracted through mining; these are then refined to extract the valuable element....

 of zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...

. It consists largely of zinc sulfide
Zinc sulfide
Zinc sulfide is a inorganic compound with the formula ZnS. ZnS is the main form of zinc in nature, where it mainly occurs as the mineral sphalerite...

 in crystal
Crystal
A crystal or crystalline solid is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions. The scientific study of crystals and crystal formation is known as crystallography...

line form but almost always contains variable iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

. When iron content is high it is an opaque black variety, marmatite. It is usually found in association with galena
Galena
Galena is the natural mineral form of lead sulfide. It is the most important lead ore mineral.Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms...

, pyrite
Pyrite
The mineral pyrite, or iron pyrite, is an iron sulfide with the formula FeS2. This mineral's metallic luster and pale-to-normal, brass-yellow hue have earned it the nickname fool's gold because of its resemblance to gold...

, and other sulfide
Sulfide
A sulfide is an anion of sulfur in its lowest oxidation state of 2-. Sulfide is also a slightly archaic term for thioethers, a common type of organosulfur compound that are well known for their bad odors.- Properties :...

s along with calcite
Calcite
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 380-470°C, and vaterite is even less stable.-Properties:...

, dolomite
Dolomite
Dolomite is a carbonate mineral composed of calcium magnesium carbonate CaMg2. The term is also used to describe the sedimentary carbonate rock dolostone....

, and fluorite
Fluorite
Fluorite is a halide mineral composed of calcium fluoride, CaF2. It is an isometric mineral with a cubic habit, though octahedral and more complex isometric forms are not uncommon...

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

Chemistry



The mineral crystallizes in the cubic crystal system
Crystal system
In crystallography, the terms crystal system, crystal family, and lattice system each refer to one of several classes of space groups, lattices, point groups, or crystals...

. In the crystal structure, zinc and sulfur atoms are tetrahedrally coordinated. The structure is closely related to the structure of diamond
Diamond
In mineralogy, diamond is an allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is less stable than graphite, but the conversion rate from diamond to graphite is negligible at ambient conditions...

. The hexagonal analog is known as the wurtzite
Wurtzite
Wurtzite is a zinc iron sulfide mineral a less frequently encountered mineral form of sphalerite. The iron content is variable up to eight percent. It is trimorphous with matraite and sphalerite....

 structure. The lattice constant for zinc sulfide in the zincblende crystal structure is 0.541 nm, calculated from geometry and ionic radii of 0.074 nm (zinc) and 0.184 nm (sulfide). It forms ABCABC layers.

Varieties



Its color is usually yellow, brown, or gray to gray-black, and it may be shiny or dull. Its luster
Lustre (mineralogy)
Lustre is a description of the way light interacts with the surface of a crystal, rock, or mineral. The word lustre traces its origins back to the Latin word lux, meaning "light", and generally implies radiance, gloss, or brilliance....

 is adamantine, resinous to submetallic for high iron varieties. It has a yellow or light brown streak, a Mohs hardness of 3.5–4, and a specific gravity
Specific gravity
Specific gravity is the ratio of the density of a substance to the density of a reference substance. Apparent specific gravity is the ratio of the weight of a volume of the substance to the weight of an equal volume of the reference substance. The reference substance is nearly always water for...

 of 3.9–4.1. Some specimens have a red iridescence
Iridescence
Iridescence is generally known as the property of certain surfaces which appear to change color as the angle of view or the angle of illumination changes...

 within the gray-black crystals; these are called "ruby sphalerite." The pale yellow and red varieties have very little iron and are translucent. The darker more opaque varieties contain more iron. Some specimens are also fluorescent
Fluorescence
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation of a different wavelength. It is a form of luminescence. In most cases, emitted light has a longer wavelength, and therefore lower energy, than the absorbed radiation...

 in ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...

 light. The refractive index
Refractive index
In optics the refractive index or index of refraction of a substance or medium is a measure of the speed of light in that medium. It is expressed as a ratio of the speed of light in vacuum relative to that in the considered medium....

 of sphalerite (as measured via sodium light, 589.3 nm) is 2.37. Sphalerite crystallizes in the isometric crystal system and possesses perfect dodecahedral cleavage
Cleavage (crystal)
Cleavage, in mineralogy, is the tendency of crystalline materials to split along definite crystallographic structural planes. These planes of relative weakness are a result of the regular locations of atoms and ions in the crystal, which create smooth repeating surfaces that are visible both in the...

. Gemmy, pale specimens from Franklin, New Jersey
Franklin, New Jersey
Franklin is a Borough in Sussex County, New Jersey, United States. As of the 2010 United States Census, the borough population was 5,045.Franklin, known as the "Fluorescent Mineral Capital of the World," is located over a rich ore body containing more than 150 minerals, many of them fluorescent and...

 (see Franklin Furnace
Franklin Furnace
Franklin Furnace, also known as the Franklin Mine, is a famous mineral location for rare zinc, iron, manganese minerals in old mines in Franklin, New Jersey, USA. This locale produced more species of minerals and more different fluorescent minerals than any other location...

) are highly fluorescent orange and/or blue under longwave ultraviolet light and are known as cleiophane, an almost pure ZnS variety.

Occurrence


Sphalerite is the major ore of zinc and is found in thousands of locations worldwide.

Sources of high quality crystals include:
  • Freiberg
    Freiberg, Saxony
    Freiberg is a city in the Free State of Saxony, Germany, administrative center of the Mittelsachsen district.-History:The city was founded in 1186, and has been a center of the mining industry in the Ore Mountains for centuries...

    , Saxony
    Saxony
    The Free State of Saxony is a landlocked state of Germany, contingent with Brandenburg, Saxony Anhalt, Thuringia, Bavaria, the Czech Republic and Poland. It is the tenth-largest German state in area, with of Germany's sixteen states....

    , and Neudorf
    Neudorf, Saxony-Anhalt
    Neudorf is a village and a former municipality in the district of Harz, in Saxony-Anhalt, Germany. Since 1 September 2010, it is part of the town Harzgerode.- History :...

    , Harz Mountains of Germany
    Germany
    Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

  • the Lengenbach Quarry
    Lengenbach Quarry
    The Lengenbach Quarry is located in the Binn Valley and it is noted among the mineralogical community for its unusual sulfosalt specimens.-Location:...

    , Binntal, Valais
    Valais
    The Valais is one of the 26 cantons of Switzerland in the southwestern part of the country, around the valley of the Rhône from its headwaters to Lake Geneva, separating the Pennine Alps from the Bernese Alps. The canton is one of the drier parts of Switzerland in its central Rhône valley...

    , Switzerland
    Switzerland
    Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....

    , has produced colorless crystals
  • Horni Slavkov
    Horní Slavkov
    Horní Slavkov is a town in Sokolov District, Karlovy Vary Region, Czech Republic. It has a population of 5,910 .-See also:*Porcelain manufacturing companies in Europe...

     (Schlaggenwald) and Pribram
    Príbram
    Příbram is a city in the Central Bohemian Region of the Czech Republic with a population of 35,147. The city is located on the Litavka river and the foothills of Brdy, 60 kilometers south-west of Prague, the country's capital...

    , Czech Republic
    Czech Republic
    The Czech Republic is a landlocked country in Central Europe. The country is bordered by Poland to the northeast, Slovakia to the east, Austria to the south, and Germany to the west and northwest....

  • From Rodna
    Rodna
    Rodna is a commune in Bistriţa-Năsăud County, Transylvania, Romania. It is composed of two villages, Rodna and Valea Vinului.During the Late Middle Ages, the Transylvanian Saxon-inhabited commune was sacked by the Mongols during their invasion of the Kingdom of Hungary....

    , Romania
    Romania
    Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...

  • Transparent green to opaque black Madan, Smolyan Province, Rhodope Mountains
    Rhodope Mountains
    The Rhodopes are a mountain range in Southeastern Europe, with over 83% of its area in southern Bulgaria and the remainder in Greece. Its highest peak, Golyam Perelik , is the seventh highest Bulgarian mountain...

    , Bulgaria
    Bulgaria
    Bulgaria , officially the Republic of Bulgaria , is a parliamentary democracy within a unitary constitutional republic in Southeast Europe. The country borders Romania to the north, Serbia and Macedonia to the west, Greece and Turkey to the south, as well as the Black Sea to the east...

    ;
  • Transparent crystals in the Aliva mine, Picos de Europa
    Picos de Europa
    The Picos de Europa is a range of mountains 20 km inland from the northern coast of Spain, located in the Autonomous Communities of Asturias, Cantabria and Castile and León, forming part of the Cantabrian Mountains...

     Mountains, Cantabria
    Cantabria
    Cantabria is a Spanish historical region and autonomous community with Santander as its capital city. It is bordered on the east by the Basque Autonomous Community , on the south by Castile and León , on the west by the Principality of Asturias, and on the north by the Cantabrian Sea.Cantabria...

     [Santander] Province, Spain
    Spain
    Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

  • In England, from Alston Moor
    Alston Moor
    Alston Moor is an area of moorland and civil parish in Cumbria, England, based around the small town of Alston. The parish had a population of 2,156 at the 2001 census. As well as the town of Alston, the parish includes the villages of Garrigill and Nenthead, along with the hamlets of Nenthall,...

    , Cumbria
    Cumbria
    Cumbria , is a non-metropolitan county in North West England. The county and Cumbria County Council, its local authority, came into existence in 1974 after the passage of the Local Government Act 1972. Cumbria's largest settlement and county town is Carlisle. It consists of six districts, and in...

  • At Dalnegorsk, Primorskiy Kray, Russia
  • From Watson Lake
    Watson Lake, Yukon
    Watson Lake is a town at historical mile 635 on the Alaska Highway in the southeastern Yukon close to the British Columbia border. Population in December 2004 was 1,547 ....

    , Yukon Territory, Canada
  • In the USA
    • the Tri-State district
      Tri-State district
      The Tri-State district was an historic lead-zinc mining district located in southwest Missouri, southeast Kansas and northeast Oklahoma. The district produced lead and zinc for over 100 years. Production began in the 1850s and 60s in the Joplin - Granby area of Jasper and Newton counties of...

       including deposits near Baxter Springs, Cherokee County, Kansas
      Cherokee County, Kansas
      Cherokee County is a county located in Southeast Kansas, in the Central United States. As of the 2010 census, the county population was 21,603. Its county seat is Columbus, and its most populous city is Baxter Springs...

      ; Joplin
      Joplin, Missouri
      Joplin is a city in southern Jasper County and northern Newton County in the southwestern corner of the US state of Missouri. Joplin is the largest city in Jasper County, though it is not the county seat. As of the 2010 census, the city population was 50,150...

      , Jasper County, Missouri
      Jasper County, Missouri
      Jasper County is a county located in the US state of Missouri. It is included in the Joplin, Missouri Metropolitan Statistical Area. The 2010 total population of Jasper County was 117,404. It is the ninth most populous county in Missouri. Its county seat is Carthage, making it one of the few...

       and Picher
      Picher, Oklahoma
      Picher is a ghost town and former city in Ottawa County, Oklahoma, United States. Formerly a major national center of lead and zinc mining at the heart of the Tri-State Mining District, over a century of unrestricted subsurface excavation dangerously undermined most of Picher's town buildings and...

      , Ottawa County, Oklahoma
      Ottawa County, Oklahoma
      Ottawa County is a county located in the U.S. state of Oklahoma. As of 2000, the population was 33,194. Its county seat is Miami. It was named for the Ottawa Tribe of Oklahoma.Ottawa County was established in 1907.-Geography:...

    • From the Elmwood mine, near Carthage
      Carthage
      Carthage , implying it was a 'new Tyre') is a major urban centre that has existed for nearly 3,000 years on the Gulf of Tunis, developing from a Phoenician colony of the 1st millennium BC...

      , Smith County, Tennessee
    • the Eagle mine, Gilman district, Eagle County, Colorado
      Eagle County, Colorado
      Eagle County is the thirteenth most populous of the 64 counties of the State of Colorado in the United States. The county is named for the Eagle River. The county population was 41,659 at U.S. Census 2000. The county seat is the Town of Eagle...

  • In Mexico
    Mexico
    The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

    , from Santa Eulalia
    Santa Eulalia, Chihuahua
    Santa Eulalia is a town and seat of the municipality of Aquiles Serdán, in the northern Mexican state of Chihuahua. As of 2005, the town had a total population of 2,089.Founded in 1652 by Diego del Castillo, it is one of the oldest settlements in the state....

     and Naica
    Naica
    Naica is a town in the Mexican state of Chihuahua. It is located in the municipality of Saucillo and reported a population of 4,775 in the 2005 INEGI Census.It is a mining town and the location of the renowned Naica Mine.-References:...

    , Chihuahua, and Cananea
    Cananea
    -Economy:Mining is the main source of revenue for Cananea and will be for the foreseeable future. Eighty percent of the population is directly or indirectly supported by mining companies in Cananea. The first and most important mining company is Mexicana de Cananea, S.A. de C.V. owned by and...

    , Sonora
    Sonora
    Sonora officially Estado Libre y Soberano de Sonora is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided into 72 municipalities; the capital city is Hermosillo....

  • Huaron, Casapalca, and Huancavelica
    Huancavelica
    Huancavelica is a city in Peru. It is the capital of the Huancavelica region and has a population of approximately 40,000. Indigenous peoples represent a major percentage of the population. It has an approximate altitude of 3,600 meters; the climate is cold and dry between the months of February...

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


Gemstone use



Crystals of suitable size and transparency have been fashioned into gemstone
Gemstone
A gemstone or gem is a piece of mineral, which, in cut and polished form, is used to make jewelry or other adornments...

s, usually featuring the brilliant cut
Brilliant (diamond cut)
A brilliant is a diamond or other gemstone, cut in a particular form with numerous facets so as to have exceptional brilliance. The shape resembles that of a cone and provides maximized light return through the top of the diamond....

 to best display sphalerite's high dispersion
Dispersion (optics)
In optics, dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency, or alternatively when the group velocity depends on the frequency.Media having such a property are termed dispersive media...

 of 0.156 (B-G interval)—over three times that of diamond
Diamond
In mineralogy, diamond is an allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is less stable than graphite, but the conversion rate from diamond to graphite is negligible at ambient conditions...

. Freshly cut gems have an adamantine luster. Owing to the softness and fragility the gems are often left unset as collector's or museum
Museum
A museum is an institution that cares for a collection of artifacts and other objects of scientific, artistic, cultural, or historical importance and makes them available for public viewing through exhibits that may be permanent or temporary. Most large museums are located in major cities...

pieces (although some have been set into pendants). Gem-quality material is usually a yellowish to honey brown, red to orange, or green.

External links