General Information:
Chemical Formula:
CaFe++2Fe+++Si2O7O(OH)
Composition:
(Molecular Weight = 408.79 gm)
Calcium 9.80 % Ca
Iron 40.98 % Fe
Silicon 13.74 % Si
Hydrogen 0.25 % H
Oxygen 35.22 % O
Empirical Formula:
CaFe2+3(SiO4)2(OH)
Environment:
Occurs with magnetite ore bodies, with zinc and copper ores, and in contact deposits and zeolites.
Locality:
Capo Calamita, on Elba.
Name Origin:
Named ilvaite from the Latin name of the island of Elba.
Physical Properties:
Cleavage:
[010] Distinct, [001] Distinct
Color:
iron black or dark grayish black.
Density:
3.99 - 4.05, Average = 4.01
Diaphaniety:
Opaque
Habits:
Striated - Parallel lines on crystal surface or cleavage face., Columnar - Forms columns, Massive - Uniformly indistinguishable crystals forming large masses.
Hardness:
5.5-6 - Knife Blade-Orthoclase
Luminescence:
None.
Luster:
Sub Metallic
Streak:
brownish black
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