Definition of Brittle silver ore

Stephanite

General Information:
 Chemical Formula:
Ag5SbS4
 Composition:
(Molecular Weight = 789.36 gm)
Silver 68.33 % Ag
Antimony 15.42 % Sb
Sulfur 16.25 % S 
 Empirical Formula:
Ag5SbS4
 Name Origin:
Named after the Austrian Mining Director engineer, Archduke Stephan (1817-1867).
Physical Properties:
 Cleavage:
[010] Imperfect, [021] Poor
 Color:
lead gray or black.
 Density:
6.2 - 6.3, Average = 6.25
 Diaphaniety:
Opaque
 Habits:
Pseudo Hexagonal - Crystals show a hexagonal outline., Tabular - Form dimensions are thin in one direction., Massive - Uniformly indistinguishable crystals forming large masses.
 Hardness:
2-2.5 - Gypsum-Finger Nail
 Luminescence:
None.
 Luster:
Metallic
 Streak:
black
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