Seligmannite

Seligmanite is a rare mineral, with the chemical formula PbCuAsS₃. Originally described from the Lengenbach Quarry, Valais Canton, Switzerland; it has also been found in the Raura district, Lima Region, Peru; at Tsumeb, Oshikoto Region, Namibia; and at the Sterling Mine, Sussex County, New Jersey, US.

Seligmannite
Seligmannite from Palomo mine, Castrovirreyna Province, Huancavelica Department, Peru
General
Category	Sulfide minerals
Formula	PbCuAsS3
IMA symbol	Seli[1]
Strunz classification	2.GA.50
Crystal system	Orthorhombic
Crystal class	Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m)
Space group	Pmmn
Identification
Formula mass	441.87 g/mol
Color	Lead gray to black
Crystal habit	Massive to crystalline
Twinning	On {110} very common
Cleavage	Indistinct on the {001}, {100}, and {010}
Fracture	Conchoidal
Tenacity	Brittle
Mohs scale hardness	3
Luster	Metallic
Streak	Black to chocolate brown
Density	5.38 – 5.44 g/cm3
Optical properties	Anisotropic
References	[2][3]