Uzonite

General Information:
 Chemical Formula:
As4S5
 Composition:
(Molecular Weight = 460.02 gm)
Arsenic 65.15 % As
Sulfur 34.85 % S 
 Empirical Formula:
As4S5
 Locality:
Uzon caldera, Kamchatka, Russia.
 Name Origin:
Named for the locality.
Physical Properties:
 Cleavage:
[001] Distinct
 Color:
yellow.
 Density:
3.37
 Habits:
Microscopic Crystals - Crystals visible only with microscopes., Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).,
 Hardness:
1.5 - Between Talc and Gypsum
 Luster:
Pearly
 Streak:
yellow
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