Teallite

Teallite is a sulfide mineral of tin and lead with chemical formula: PbSnS₂. It occurs in hydrothermal veins and is sometimes mined as an ore of tin. Teallite forms soft silvery grey mica-like plates and crystallizes in the orthorhombic system. The Mohs hardness is 1.5 to 2 and the specific gravity is 6.4.

Teallite
General
Category	Sulfide minerals
Formula (repeating unit)	PbSnS2
Strunz classification	2.CD.05
Crystal system	Orthorhombic
Crystal class	Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m)
Space group	Pbnm (no. 62)
Unit cell	a = 4.26 Å, b = 11.41 Å c = 4.09 Å; Z = 2
Identification
Color	Silvery gray, lead-gray to iron-gray; tarnishes dull or iridescent
Cleavage	{001} perfect (lamellar cleavage); flexible
Tenacity	Malleable
Mohs scale hardness	​1 1⁄2 - 2
Luster	Metallic
Streak	Black
Diaphaneity	Opaque
Specific gravity	6.36
Optical properties	Anisotropic
Pleochroism	Weak
References	[1][2]

Teallite was first described in 1904 from its type locality in Santa Rosa, Antequera, Bolivia. It was named for the British geologist Jethro Justinian Harris Teall (1849–1924).

This article uses material from the Wikipedia article  Metasyntactic variable, which is released under the  Creative Commons Attribution-ShareAlike 3.0 Unported License.