General Information:
Chemical Formula:
(Na,K)(Mn++++,Mn++)8O16·n(H2O)
IMA Status:
Approved IMA 1968
Physical Properties:
Cleavage:
None
Color:
brownish gray, gray brown, or dark brown gray.
Density:
4.29
Diaphaniety:
Opaque
Hardness:
7 - Quartz
Luster:
Earthy (Dull)
Streak:
brownish black
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