General Information:
Chemical Formula:
(Mg,Fe++)7(SiO4)3(F,OH)2
Composition:
(Molecular Weight = 538.58 gm)
Magnesium 23.69 % Mg
Iron 18.15 % Fe
Silicon 15.64 % Si
Hydrogen 0.09 % H
Oxygen 37.13 % O
Fluorine 5.29 % F
Empirical Formula:
Mg5.25Fe2+1.75(SiO4)3F1.5(OH)0.5
Environment:
Commonly interlayered with clinohumite.
Locality:
Mte. Somma, Vesuvius, Italy.
Physical Properties:
Cleavage:
[001] Poor
Color:
brown, yellow, white, or dark orange.
Density:
3.1 - 3.2, Average = 3.15
Diaphaniety:
Transparent to translucent
Hardness:
6-6.5 - Orthoclase-Pyrite
Luster:
Vitreous (Glassy)
Streak:
white
More details...