Canfieldite

Canfieldite
240px Canfieldite
General
Category	Sulfide minerals
Formula (repeating unit)	Ag8SnS6
Strunz classification	02.BA.70
Identification
Color	Steel gray with reddish tint
Crystal system	Orthorhombic
Fracture	Irregular/ uneven, conchoidal
Tenacity	Brittle
Mohs scale hardness	2½
Luster	Metallic
Streak	Greyish black
Diaphaneity	Opaque
Density	6.2 - 6.3 g/cm3

Canfieldite is a rare silver tin sulfide mineral with formula: Ag₈SnS₆. The mineral typically contains variable amounts of germanium substitution in the tin site and tellurium in the sulfur site. There is a complete series between canfieldite and its germanium analogue, argyrodite. It forms black orthorhombic crystals which often appear to be cubic in form due to twinning. The most typical form is as botryoidal rounded grape-like masses. Its Mohs hardness is 2.5 and the specific gravity is 6.28. Canfieldite exhibits conchoidal fracturing and no cleavage.

Canfieldite was first described in 1893 from an occurrence in Colquechaca, Potosí Department, Bolivia. It was named for Frederick Alexander Canfield (1849–1926), an American mining engineer.

See also

• List of minerals
• List of minerals named after people

References

• Mindat with location data
• Webmineral data