Erlichmanite

Erlichmanite is the naturally occurring mineral form of osmium sulfide (OsS₂). It is grey with a metallic luster, hardness around 5, and specific gravity about 9.^[2] It is found in noble metal placer deposits.^[3] Named for Jozef Erlichman, electron microprobe analyst at the NASA Ames Research Center.^[4]

Erlichmanite
General
Category	Pyrite
Formula	OsS2
IMA symbol	Erl[1]
Strunz classification	2/D.17-110
Dana classification	2.12.1.16
Crystal system	Isometric
Crystal class	Diploidal
Unit cell	177.47 ų
Identification
Formula mass	254.33gm
Colour	Grey
Crystal habit	Pyritohedral crystals or grains
Mohs scale hardness	4.5-5.5
Luster	Metallic
Diaphaneity	Opaque
Specific gravity	8.28
Density	8.28 g/cm3 (Measured), 9.59 g/cm3 (Calc)
Pleochroism	Non-pleochromic
Common impurities	Iridium, Rhodium, Ruthenium, Paladium