General Information:
Chemical Formula:
(Na,K)(Fe+++,Fe++)3(Fe,Mg,Al)6(BO3)3Si6O18(OH)4
Composition:
(Molecular Weight = 1,332.93 gm)
Potassium 0.73 % K
Sodium 1.29 % Na
Magnesium 3.28 % Mg
Aluminum 1.21 % Al
Iron 27.65 % Fe
Silicon 12.64 % Si
Boron 4.87 % B
Hydrogen 0.30 % H
Oxygen 48.01 % O
Empirical Formula:
Na0.75K0.25Fe3+2.25Fe2+0.75Fe2+3.6Mg1.8Al0.6(BO3)3(Si6O
IMA Status:
Approved IMA
Physical Properties:
Cleavage:
None
Color:
black.
Density:
3.26
Diaphaniety:
Translucent
Hardness:
7 - Quartz
Luster:
Resinous
Streak:
brown
More details...