Stannite

Stannite
General
Category	Sulfide mineral
Formula (repeating unit)	Cu2FeSnS4
IMA symbol	Stn[1]
Strunz classification	2.CB.15a
Crystal system	Tetragonal
Crystal class	Scalenohedral (42m) H-M symbol: (4 2m)
Space group	I42m
Unit cell	a = 5.4432, c = 10.7299 [Å]; Z = 2
Identification
Color	Steel-gray to iron-black, may tarnish blue
Crystal habit	Rarely as pseudo-octahedral crystals also massive, granular, and disseminated
Twinning	Penetration twins on {102}
Cleavage	Indistinct on {110} and {001}
Fracture	Uneven
Mohs scale hardness	4
Luster	Metallic
Streak	Black
Diaphaneity	Opaque
Specific gravity	4.3 – 4.5
References	[2][3][4]

Stannite is a mineral, a sulfide of copper, iron, and tin, in the category of thiostannates.

Background

The chemical formula is Cu₂FeSnS₄. Zinc commonly occurs with the iron and trace germanium may be present.[4] Stannite is used as an ore of tin, consisting of approximately 28% tin, 13% iron, 30% copper, 30% sulfur by mass. It is found in tin-bearing, hydrothermal vein deposits occurring with chalcopyrite, sphalerite, tetrahedrite, arsenopyrite, pyrite, cassiterite, and wolframite.[2]

It is also known as bell metal ore as tin is an important constituent of bell-metal. It is thought the exploitation of tin deposits in Cornwall led to an expansion in bell founding.

The name comes from the Latin for tin: stannum. It was first described in 1797 for an occurrence in Wheal Rock, St. Agnes, Cornwall, England.[4]

See also

• Kesterite

References

1. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
2. "Stannite" (PDF). Handbook of Mineralogy.
3. "Stannite". Webmineral data.
4. "Stannite". Mindat.org.