General Information:
Chemical Formula:
NaCa2(Fe++4Al)Si6Al2O22(OH)2
Composition:
(Molecular Weight = 961.99 gm)
Sodium 2.39 % Na
Calcium 8.33 % Ca
Aluminum 8.41 % Al
Iron 23.22 % Fe
Silicon 17.52 % Si
Hydrogen 0.21 % H
Oxygen 39.92 % O
Empirical Formula:
NaCa2Fe2+4Al(Si6Al2O22)(OH)2
IMA Status:
Approved IMA 1978
Physical Properties:
Cleavage:
[110] Perfect
Color:
bluish green, brown, grayish black, or black.
Density:
3.44
Diaphaniety:
Translucent to Subopaque
Hardness:
5-6 - Between Apatite and Orthoclase
Luster:
Vitreous (Glassy)
Streak:
gray white
More details...