Arsenpolybasite

General Information:
 Chemical Formula:
(Ag,Cu)16(As,Sb)2S11
 Composition:
(Molecular Weight = 2,074.59 gm)
Copper 12.25 % Cu
Silver 62.39 % Ag
Antimony 2.93 % Sb
Arsenic 5.42 % As
Sulfur 17.00 % S 
 Empirical Formula:
Ag12Cu4As1.5Sb0.5S11
 IMA Status:
Approved IMA 1963
Physical Properties:
 Cleavage:
[???] Indistinct, [001] Distinct
 Color:
black.
 Density:
6.18 - 6.23, Average = 6.2
 Diaphaniety:
Opaque
 Hardness:
3 - Calcite
 Luster:
Metallic
 Streak:
black
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