General Information:
Chemical Formula:
(Cu,Ag)21(Pb,Bi)2S13
Composition:
(Molecular Weight = 2,256.15 gm)
Copper 53.51 % Cu
Silver 9.56 % Ag
Bismuth 9.26 % Bi
Lead 9.18 % Pb
Sulfur 18.48 % S
Empirical Formula:
Cu19Ag2PbBiS13
IMA Status:
Approved IMA 1972
Locality:
Foster mine, Cobalt, Ontario, Canada.
Name Origin:
Named for Fed LaRose, a discoverer of silver ore at Cobalt.
Physical Properties:
Color:
black.
Density:
6.19
Diaphaniety:
Opaque
Habits:
Microscopic Crystals - Crystals visible only with microscopes., Acicular - Occurs as needle-like crystals.,
Hardness:
3-3.5 - Calcite-Copper Penny
Luster:
Metallic
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