Sarkinite

General Information:
 Chemical Formula:
Mn++2(AsO4)(OH)
 Composition:
(Molecular Weight = 265.80 gm)
Manganese 41.34 % Mn
Arsenic 28.19 % As
Hydrogen 0.38 % H 
Oxygen 30.10 % O 
 Empirical Formula:
Mn2+2(AsO4)(OH)
Physical Properties:
 Cleavage:
[100] Distinct
 Color:
yellow, dark red, or reddish yellow.
 Density:
4.08 - 4.18, Average = 4.13
 Hardness:
4-5 - Fluorite-Apatite
 Luster:
Greasy (Oily)
 Streak:
yellow
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