Takeuchiite

General Information:
 Chemical Formula:
Mg2Mn+++O2(BO3)
 Composition:
(Molecular Weight = 253.16 gm)
Magnesium 19.20 % Mg
Manganese 21.70 % Mn
Boron 8.54 % B 
Oxygen 50.56 % O 
 Empirical Formula:
Mg2Mn3+O2(BO3)
 Environment:
In dolomite.
 IMA Status:
Approved IMA 1980
 Locality:
Lanban, Varmland, Sweden.
 Name Origin:
Named for Yoshio Takeuchi (1924-), Japanese mineralogist
Physical Properties:
 Cleavage:
None
 Color:
black.
 Density:
3.93
 Diaphaniety:
Opaque
 Hardness:
6 - Orthoclase
 Luster:
Metallic
 Streak:
brown
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