General Information:
Chemical Formula:
(Ca,Na)(Fe,Mg,Ti)3(Al,Mg,Fe)6(BO3)3Si6O18(OH)4
Composition:
(Molecular Weight = 1,224.34 gm)
Sodium 0.47 % Na
Calcium 2.46 % Ca
Magnesium 5.36 % Mg
Titanium 1.17 % Ti
Aluminum 7.93 % Al
Iron 10.95 % Fe
Silicon 13.76 % Si
Boron 5.30 % B
Hydrogen 0.33 % H
Oxygen 52.27 % O
Empirical Formula:
Ca0.75Na0.25Fe2+2.4Mg2.7Ti0.3Al3.6(BO3)3Si6O18(OH)4
IMA Status:
Approved IMA
Physical Properties:
Cleavage:
None
Color:
brownish black, dark brown, or black.
Density:
3.207
Diaphaniety:
Translucent to Opaque
Hardness:
7 - Quartz
Luster:
Vitreous - Dull
Streak:
gray
More details...