Aerugite

Aerugite is a rare complex nickel arsenate mineral with a variably reported formula: Ni₉(AsO₄)₂AsO₆. It forms green to deep blue-green trigonal crystals. It has a Mohs hardness of 4 and a specific gravity of 5.85 to 5.95.

Aerugite
General
Category	Arsenate minerals
Formula	Ni9(AsO4)2AsO6
IMA symbol	Aru[1]
Strunz classification	8.BC.15
Crystal system	Trigonal
Crystal class	Hexagonal scalenohedral (3m) H-M symbol: (3 2/m)
Space group	R3m
Identification
Color	Grass green, blue-green
Crystal habit	Massive to crystalline crusts
Mohs scale hardness	4
Luster	Adamantine
Streak	light green, greenish white
Diaphaneity	Opaque to semitransparent
Specific gravity	5.85–5.95
References	[2][3][4]

It was first described in 1858 in either the South Terres mine of Cornwall, England or in the Ore Mountains, Saxony, Germany. The origin is disputed. The most common occurrence is as an incrustation on furnace walls in which ores are roasted. Its name comes from the Latin word aerugo for copper rust.

See also

• List of minerals