Johnsomervilleite

General Information:
 Chemical Formula:
Na2Ca(Mg,Fe++,Mn)7(PO4)6
 IMA Status:
Approved IMA 1979
Physical Properties:
 Cleavage:
[???] Perfect
 Color:
dark brown.
 Density:
3.35
 Diaphaniety:
Transparent to Translucent
 Hardness:
4.5 - Between Fluorite and Apatite
 Luster:
Vitreous (Glassy)
 Streak:
light brown
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