General Information:
Chemical Formula:(K,Na)3(Mn,Fe++)7(Ti,Nb)2Si8O24(O,OH)7
Composition:(Molecular Weight = 1,333.33 gm)Potassium 6.60 %
K Sodium 1.29 %
NaTitanium 5.39 %
TiManganese 21.63 %
MnNiobium 3.48 %
NbIron 7.33 %
FeSilicon 16.85 %
SiHydrogen 0.23 %
H Oxygen 37.20 %
O Empirical Formula: K2.25Na0.75Mn2+5.25Fe2+1.75Ti1.5Nb0.5Si8O28(OH)3
Locality:Lovozero massif, Kola Peninsula, Russia.
Name Origin:Named for Boris Mikhailovich Kupletski (1984-1964) and Elsa Maximilianove Bohnshtedt Kupletskaya (1897-1974), Russian geologists.
Physical Properties: Cleavage:[001] Perfect
Color:yellow brown, black, or black brown.
Density:3.2 - 3.23, Average = 3.21
Diaphaniety:Translucent to Opaque
Habits:Tabular - Form dimensions are thin in one direction., Acicular - Occurs as needle-like crystals.,
Hardness:4 - Fluorite
Luster:Vitreous - Adamantine
Streak:brown
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