Tennantite

Formula	(Cu, Ag, Zn, Fe)12As4S13
Origin	Tsumeb Mine (Namibia)
Description	greyish tennantite crystal
Classification (Lapis)	Sulfides
Crystal System	Cubic
Hardness	3,0 – 4,5
Colour	Flint-gray to iron-black, cherry-red in transmitted light; in polished section, gray inclining to black to brown to cherry-red
Streak	red-brown, black
Luminescence	none observed
Lustre	Metallic
Transparency (Opacity)	Opaque
Cleavage
Fracture	subconchoidal to uneven
Magnetism	Negative
Geological Setting	In hydrothermal veins and contact metamorphic deposits
Specific Gravity	4,61 g/cm3