General Information:
Chemical Formula:(Ce,Th,Ca)5(Si,B)3O12(OH,F)·n(H2O)
Environment:Alkalic rocks and their cogenetic pegmatites. Also in metamorphosed alkalic rocks.
IMA Status:Approved IMA 1987
Locality:Isle of Kjeo in the Langesundfiord district, southern Norway.
Name Origin:Named froom the Greek meaning "black" and the composition (Cerium).
Physical Properties: Cleavage:None
Color:brown, black, dark brown, or reddish brown.
Density:4.13
Diaphaniety:Subtransparent to opaque
Habits:Tabular - Form dimensions are thin in one direction., Metamict - Mineral originally crystalline, now amorphous due to radiation damage.,
Hardness:5-6 - Between Apatite and Orthoclase
Luminescence:Radioactive.
Luster:Resinous
Streak:light brown
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