General Information:
Chemical Formula:
NaNa2Mn++4(Fe+++,Al)Si8O22(OH)2
Composition:
(Molecular Weight = 948.04 gm)
Sodium 7.27 % Na
Manganese 23.18 % Mn
Aluminum 0.71 % Al
Iron 4.42 % Fe
Silicon 23.70 % Si
Hydrogen 0.21 % H
Oxygen 40.50 % O
Empirical Formula:
Na3Mn2+4Fe3+0.75Al0.25Si8O22(OH)2
IMA Status:
Approved IMA 1969
Physical Properties:
Cleavage:
[110] Perfect
Color:
reddish black or black.
Density:
3.3
Diaphaniety:
Transparent to Translucent
Hardness:
5 - Apatite
Luster:
Vitreous (Glassy)
Streak:
light purple brown
More details...