Kaersutite

General Information:
 Chemical Formula:
NaCa2(Mg4Ti)Si6Al2O23(OH)2
 Composition:
(Molecular Weight = 872.72 gm)
Sodium 2.63 % Na
Calcium 9.18 % Ca
Magnesium 11.14 % Mg
Titanium 5.49 % Ti
Aluminum 6.18 % Al
Silicon 19.31 % Si
Hydrogen 0.23 % H 
Oxygen 45.83 % O 
 Empirical Formula:
NaCa2Mg4Ti(Si6Al2O23)(OH)2
 IMA Status:
Approved IMA 1978
Physical Properties:
 Cleavage:
[110] Perfect
 Color:
dark brown or black.
 Density:
3.2 - 3.28, Average = 3.24
 Diaphaniety:
Translucent to Subopaque
 Hardness:
5-6 - Between Apatite and Orthoclase
 Luster:
Vitreous - Resinous
 Streak:
brownish gray
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KAERSUTITE