Sphalerite facts for kids

Quick facts for kids Sphalerite
General
Category	Sulfide mineral
Formula (repeating unit)	(Zn,Fe)S
Strunz classification	2.CB.05a
Dana classification	02.08.02.01
Crystal symmetry	F43m (No. 216)
Unit cell	a = 5.406 Å; Z = 4
Identification
Color	Brown, yellow, red, green, black.
Crystal habit	Euhedral crystals – occurs as well-formed crystals showing good external form. Granular – generally occurs as anhedral to subhedral crystals in matrix.
Crystal system	Cubic
Twinning	Simple contact twins or complex lamellar forms, twin axis [111]
Cleavage	perfect
Fracture	Uneven to conchoidal
Mohs scale hardness	3.5-4
Luster	Adamantine, resinous, greasy
Streak	brownish white, pale yellow
Diaphaneity	Transparent to translucent, opaque when iron-rich
Specific gravity	3.9–4.2
Optical properties	Isotropic
Refractive index	nα = 2.369
Other characteristics	non-radioactive, non-magnetic, fluorescent and triboluminescent.

Sphalerite is a mineral. Its is a mixed zinc and iron sulfide. The chemical formula is (Zn,Fe)S. It can be brown, yellow, red, green, and black. It is normally found with galena, a lead ore. It is also known as zinc blende. It has a Mohs hardness of 3.5 to 4. It is the main ore of zinc. It has a non-metalic sheen.

Localities

The top producers of sphalerite include the United States, Russia, Mexico, Germany, Australia, Canada, China, Ireland, Peru, Kazakhstan and England.

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, 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 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). Similarly to 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 intrusions in yule marble, which is used as a building material for the Lincoln Memorial 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

Images for kids

• 

  The crystal structure of sphalerite

• 

  Sharp, tetrahedral sphalerite crystals with minor associated chalcopyrite from the Idarado Mine, Telluride, Ouray District, Colorado, US (size: 2.3×2.3×1.2 cm)

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  Gem quality twinned cherry-red sphalerite crystal (1.8 cm) from Hunan Province, China

• 

  faceted Sphalerite, 3.86ct, Spain

See also

In Spanish: Esfalerita para niños