Chemistry:Rammelsbergite

Rammelsbergite
General
Category	Mineral
Formula (repeating unit)	NiAs2
Strunz classification	2.EB.15a
Crystal system	Orthorhombic
Crystal class	Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m)
Space group	Pnnm
Unit cell	a = 4.759 Å, b = 5.797 Å c = 3.539 Å; Z = 2
Identification
Color	Tin white with a faint pinkish hue
Crystal habit	Rarely as prismatic crystals; commonly massive, granular, radial, fibrous
Twinning	On {101}
Cleavage	Distinct on {101}
Fracture	Irregular
Tenacity	Brittle
Mohs scale hardness	5.5–6
|re|er}}	Metallic
Streak	Grayish black
Diaphaneity	Opaque
Specific gravity	7.0–7.1
Optical properties	Strongly anisotropic
Pleochroism	Weak, yellow to pinkish hue and bluish white
References

Rammelsbergite is a nickel arsenide mineral with formula NiAs₂. It forms metallic silvery to tin white to reddish orthorhombic prismatic crystals, and is usually massive in form. It has a Mohs hardness of 5.5 and a specific gravity of 7.1.

It was first described in 1854 from its type locality in the Schneeberg District in Saxony, Germany . It was named after the Germany chemist and mineralogist, Karl Friedrich August Rammelsberg (1813–1899).

It occurs as a hydrothermal mineral in medium temperature veins association with skutterudite, safflorite, lollingite, nickeline, native bismuth, native silver, algodonite, domeykite and uraninite.

See also

• List of minerals named after people

References

• Mineral Galleries
• Schumann, Walter (1991). Mineralien aus aller Welt. BLV Bestimmungsbuch (2 ed.). pp. 223. ISBN 978-3-405-14003-8.