General Information:
Chemical Formula:
Ca2(Mn,Fe++)Fe+++Si5O14(OH)
Composition:
(Molecular Weight = 572.59 gm)
Calcium 14.00 % Ca
Manganese 7.20 % Mn
Iron 12.19 % Fe
Silicon 24.52 % Si
Hydrogen 0.18 % H
Oxygen 41.91 % O
Empirical Formula:
Ca2Mn2+0.75Fe2+0.25Fe3+Si5O14(OH)
IMA Status:
Approved IMA 1967
Physical Properties:
Cleavage:
[001] Perfect, [110] Indistinct
Color:
black or brownish black.
Density:
3.45
Diaphaniety:
Subtranslucent
Hardness:
5.5-6 - Knife Blade-Orthoclase
Luster:
Vitreous (Glassy)
Streak:
brownish
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