Xanthoconite

General Information:
 Chemical Formula:
Ag3AsS3
 Composition:
(Molecular Weight = 494.72 gm)
Silver 65.41 % Ag
Arsenic 15.14 % As
Sulfur 19.44 % S 
 Empirical Formula:
Ag3AsS3
 Locality:
Freiberg, Germany.
 Name Origin:
From the Greek xanthos, "yellow" and konis "powder."
Physical Properties:
 Cleavage:
[001] Distinct
 Color:
dark crimson red, dark orange, brown, or lemon yellow.
 Density:
5.5 - 5.6, Average = 5.55
 Diaphaniety:
Subtranslucent to opaque
 Habits:
Massive - Granular - Common texture observed in granite and other igneous rock., Reniform - "Kidney like" in shape (e.g.. hematite)., Tabular - Form dimensions are thin in one directi on.
 Hardness:
2.5-3 - Finger Nail-Calcite
 Luminescence:
None.
 Luster:
Adamantine
 Streak:
orange yellow
More details...

XANTHOCONITE