General Information:
Chemical Formula:
(Y,Ca,La,Fe++)5(Si,B,Al)3(O,OH,F)13 (?)
Composition:
(Molecular Weight = 693.60 gm)
Calcium 8.67 % Ca
Lanthanum 20.03 % La
Yttrium 25.64 % Y
Aluminum 1.17 % Al
Iron 4.03 % Fe
Silicon 8.10 % Si
Boron 1.09 % B
Hydrogen 0.44 % H
Oxygen 25.37 % O
Fluorine 5.48 % F
Empirical Formula:
5(Y0.4)5(Ca0.3)5(La0.2)5(Fe2+0.1)Si2B0.7Al0.3O8(OH)3F2
Environment:
Granite pegmatites.
IMA Status:
Approved IMA 1987
Locality:
Cranberry Lake, Sussex County, New Jersey, USA.
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:
greenish black, dark green black, or reddish brown.
Density:
3.05 - 3.4, Average = 3.22
Diaphaniety:
Translucent to Subopaque
Habits:
Pyramidal - Crystals are shaped like pyramids., Metamict - Mineral originally crystalline, now amorphous due to radiation damage.,
Hardness:
3.5-6.5
Luster:
Vitreous - Resinous
More details...