Auricupride

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Auricupride
Auricupride-133536.jpg
Auricupride
General
Category Native elements
Formula
(repeating unit)
Cu3Au
Strunz classification 1.AA.10a
Dana classification 1.1.2.1
Crystal system Cubic
Hexoctahedral class
Identification
Formula mass 387.60 g/mol
Color Yellow with reddish tint
Crystal symmetry Isometric
H-M symbol: (4/m 3 2/m)
Space group: Pm3m
Fracture Malleable
Mohs scale hardness
Luster Metallic
Streak yellow
Diaphaneity Opaque
Ultraviolet fluorescence Non-fluorescent
References [1][2][3][4]

Auricupride is a natural alloy that combines copper and gold. Its chemical formula is Cu3Au. The alloy crystallizes in the Cubic crystal system and occurs as malleable grains or platey masses. It is an opaque yellow with a reddish tint. It has a hardness of 3.5 and a specific gravity of 11.5.[2]

A variant called tetra-auricupride (CuAu) exists. Silver may be present resulting in the variety argentocuproauride (Cu3(Au,Ag)).[1]

It was first described in 1950 for an occurrence in the Ural Mountains Russia. It occurs as low temperature unmixing product in serpentinites and as reduction "halos" in redbed deposits. It is most often found in Chile, Argentina, Tasmania, Russia, Cyprus, Switzerland and South Africa.[2][1]

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