General Information:
Chemical Formula:
(Ce,La,Ca,Y,Th)5(Si,B)3(O,OH,F)13
Composition:
(Molecular Weight = 787.79 gm)
Calcium 10.17 % Ca
Lanthanum 17.63 % La
Cerium 26.68 % Ce
Yttrium 3.95 % Y
Thorium 4.42 % Th
Silicon 8.91 % Si
Boron 0.69 % B
Hydrogen 0.38 % H
Oxygen 22.34 % O
Fluorine 4.82 % F
Empirical Formula:
5(Ce0.3)5(Ca0.4)5(La0.2)5(Y0.07)5(Th0.03)Si2.5B0.5O8(OH)3F2
Environment:
Nepheline Syenite.
IMA Status:
Approved IMA 1987
Locality:
Laven Island, Langesundfiord district, near Brevik, southern Norway.
Name Origin:
Named from the Greek for "three" and "to cut," in allusion to the trihedral cavities left in the host rock by the crystals.
Physical Properties:
Cleavage:
None
Color:
dark brown.
Density:
4.2
Diaphaniety:
Translucent to Subopaque
Habits:
Pyramidal - Crystals are shaped like pyramids., Metamict - Mineral originally crystalline, now amorphous due to radiation damage.,
Hardness:
5.5 - Knife Blade
Luster:
Vitreous - Resinous
More details...