General Information:
Chemical Formula:
(Fe+++,Fe++,Ti)7Sb+++O13(OH)
Name Origin:
Named after the american geologist Orville A. Derby
Physical Properties:
Cleavage:
None
Color:
pitch black or black.
Density:
4.53
Diaphaniety:
Opaque
Hardness:
5 - Apatite
Luster:
Resinous
Streak:
brownish black
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