Arsenopyrite

Formula	FeAsS
Origin	Panasqueira Mine (Portugal)
Description
Classification (Lapis)	Sulfides
Crystal System	monoclinic
Hardness	5,5 – 6,0
Colour	silver-white to steel-gray; in polished section, white with faint yellow tint
Streak	grey-black to black
Luminescence	none observed
Lustre	metallic
Transparency (Opacity)	opaque
Cleavage	distinct
Fracture	uneven
Magnetism	negative
Geological Setting	of hydrothermal origin, typically one of the earliest minerals to form
Specific Gravity	6,18 g/cm3