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Domeykite with Copper

#BAC62654

Domeykite with Copper

#BAC62654
Availability
Sold
Size
7.5 x 4.5 x 2 cm - Sm Cabinet 
Formula
Cu3As (RRUFF)
Locality
Cashin mine, Montrose Co., Colorado, United States
Tagged
copper

This is weird, but interesting specimen and is definitely an old-timer from the Cashin mine in Colorado. The Cashin mine is located in the La Sal Creek district near the Cliff Dweller mine in Montrose county. Reports show that ore produced prior to 1920 contained 35 to 50% Copper and 8-10 ounces of Silver per ton. This specimen is composed of Copper and Domeykite and probably a lot of Silver. Some parts are harder (3.5) and when scratched show a silvery luster, which is the Domeykite. Other parts show a copper luster and is obviously softer and malleable. Silver is also seen when scratched. I am inclined to think this specimen is a mixture of the three minerals much like an alloy. There are areas where nice but mal-formed crystals of Copper can be seen.

Domeykite

Formula
Cu3As 
Crystal System
Isometric 
Crystal Habit
Botryoidal, Reniform, Massive 
Cleavage
None, None, None 
Luster
Metallic 
Color
gray, yellow brown, silver white, tin white 
Streak
black gray 
Class
Isometric - Hextetrahedral 
Fracture
Brittle - Sectile 
Hardness
3-3.5 

Data courtesy of Webmineral.

Collection
Chet S. Lemanski, Jr. Collection
Mineralpedia
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Previously Sold Domeykite
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Other Available Domeykite
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