General Information:
Chemical Formula:(Na,K,Pb,Li)3(Ta,Nb,Al)11(O,OH)30
Environment:In alluvial concentrates. Probalby derived from the alteration of simpsonite in a lithium pegmatite.
IMA Status:Approved IMA 1969
Locality:Mumba, Kivu, Zaire.
Name Origin:Named for Kalervo Rankama (1913-), Finnish geochemist, University of Helsinki.
Physical Properties: Cleavage:None
Color:white or creamy white.
Density:5.5
Diaphaniety:Transparent
Habits:Massive - Uniformly indistinguishable crystals forming large masses., Fibrous - Crystals made up of fibers., Acicular - Occurs as needle-like crystals.
Hardness:3-4 - Calcite-Fluorite
Luster:Adamantine
Streak:white
More details...
