General Information:
Chemical Formula:
(K,Na)1-x(Ta,Nb,Al)4(O,OH)11
Environment:
Granite pegmatites.
IMA Status:
Approved IMA 1982
Locality:
Kola Peninsula, Russia.
Name Origin:
Named for A. F. Sosedko (1901-1957), Russian mineralogist.
Physical Properties:
Cleavage:
None
Color:
colorless.
Density:
6.9
Diaphaniety:
Transparent
Hardness:
6 - Orthoclase
Luminescence:
Non-fluorescent.
Luster:
Adamantine
Streak:
white
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