Dioptase

Formula	CuSiO3•H2O
Origin	Tsumeb (Namibia)
Description	intense green crystals
Classification (Lapis)	Silicates
Crystal System	trigonal
Hardness	5,0
Colour	emerald-green, blue-green.
Streak	green
Luminescence	none observed
Luster	vitreous
Transparency (Opacity)	translucent
Cleavage	perfect
Fracture	conchoidal to uneven
Magnetism	negative
Geological Setting	in the oxidized zone of some copper deposits
Specific Gravity	3,30 g/cm3