General Information:
Chemical Formula:
K(Mn++,Fe+++,Fe++)2(Nb,Ta)(PO4)2O2((H2O),OH)2
IMA Status:
Approved IMA
Physical Properties:
Cleavage:
[001] Good, [100] Good
Color:
dark reddish brown or reddish brown.
Density:
3.4
Diaphaniety:
Transparent to Translucent
Hardness:
4 - Fluorite
Luster:
Vitreous (Glassy)
Streak:
greenish yellow
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