Fangite

General Information:
 Chemical Formula:
Tl3AsS4
 Composition:
(Molecular Weight = 816.34 gm)
Thallium 75.11 % Tl
Arsenic 9.18 % As
Sulfur 15.71 % S 
 Empirical Formula:
Tl3AsS4
 Environment:
Found in vugs with pyrite an other sulfide material of complex composition.
 IMA Status:
Approved IMA
 Locality:
Mercur gold deposit in the southern Oquirrh Mountains of Tooele County, Utah, USA.
 Name Origin:
Fangite was named for Jen-Ho Fang in honor of his numerous contributions to crystallography, crystal chemistry, and geostatistics.
Physical Properties:
 Cleavage:
[???] Indistinct
 Color:
deep dark brown or red.
 Density:
6.185
 Diaphaniety:
Translucent
 Hardness:
2-2.5 - Gypsum-Finger Nail
 Luster:
Sub Metallic
 Streak:
orange
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