General Information:
Chemical Formula:
[ ]Na2(Fe++3Al2)Si8O22(OH)2
Composition:
(Molecular Weight = 878.17 gm)
Sodium 5.24 % Na
Aluminum 6.14 % Al
Iron 19.08 % Fe
Silicon 25.59 % Si
Hydrogen 0.23 % H
Oxygen 43.73 % O
Empirical Formula:
Na2Fe2+3Al2(Si8O22)(OH)2
IMA Status:
Approved IMA 1978
Physical Properties:
Cleavage:
[110] Perfect
Color:
blue, blue black, gray, or gray blue.
Density:
3.04 - 3.23, Average = 3.13
Diaphaniety:
Transparent to Translucent
Hardness:
6 - Orthoclase
Luster:
Vitreous - Dull
Streak:
blue gray
More details...