Orthochamosite

General Information:
 Chemical Formula:
(Fe++,Mg,Fe+++)5Al(Si3Al)O10(OH,O)8
 Composition:
(Molecular Weight = 664.18 gm)
Magnesium 5.49 % Mg
Aluminum 8.12 % Al
Iron 29.43 % Fe
Silicon 12.69 % Si
Hydrogen 0.91 % H 
Oxygen 43.36 % O 
 Empirical Formula:
Fe2+3Mg1.5Fe3+0.5Al2Si3O12(OH)6
Physical Properties:
 Cleavage:
[???] Good
 Color:
green, greenish gray, or black.
 Density:
3.1 - 3.15, Average = 3.12
 Diaphaniety:
Transparent to Translucent
 Hardness:
2.5-3.5 - Finger Nail-Copper Penny
 Luster:
Pearly
 Streak:
greenish white
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