Chemistry:Stannite

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Stannite
Stannite-Chalcopyrite-Quartz-168837.jpg
General
CategorySulfide mineral
Formula
(repeating unit)
Cu2FeSnS4
Strunz classification2.CB.15a
Crystal systemTetragonal
Crystal classScalenohedral (42m)
H-M symbol: (4 2m)
Space groupI42m
Unit cella = 5.4432, c = 10.7299 [Å]; Z = 2
Identification
ColorSteel-gray to iron-black, may tarnish blue
Crystal habitRarely as pseudo-octahedral crystals also massive, granular, and disseminated
TwinningPenetration twins on {102}
CleavageIndistinct on {110} and {001}
FractureUneven
Mohs scale hardness4
|re|er}}Metallic
StreakBlack
DiaphaneityOpaque
Specific gravity4.3 - 4.5
References[1][2][3]

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

Background

The chemical formula Cu2FeSnS4. Zinc commonly occurs with the iron and trace germanium may be present.[3] 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.[1]

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 .[3]

See also

References