Gamagarite

General Information:
 Chemical Formula:
Ba2(Fe+++,Mn+++)(VO4)2(OH)
 Composition:
(Molecular Weight = 577.16 gm)
Barium 47.59 % Ba
Manganese 2.38 % Mn
Vanadium 17.65 % V 
Iron 7.26 % Fe
Hydrogen 0.17 % H 
Oxygen 24.95 % O 
 Empirical Formula:
Ba2Fe3+0.75Mn3+0.25(VO4)2(OH)
Physical Properties:
 Cleavage:
[001] Distinct, [100] Distinct, [101] Indistinct
 Color:
brownish black, dark brown, or black.
 Density:
4.62
 Diaphaniety:
Translucent to Opaque
 Hardness:
4.5-5
 Luster:
Adamantine
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