Hedenbergite

Hedenbergite, calcium iron pyroxene CaFeSi2O6, is a black mineral closely allied to diopside and, owing to the isomorphous replacement of iron by magnesium, there is no sharp line of division between them.
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General Information:
 Chemical Formula:
CaFe++Si2O6
 Composition:
(Molecular Weight = 248.09 gm)
Calcium 16.15 % Ca
Iron 22.51 % Fe
Silicon 22.64 % Si
Oxygen 38.69 % O 
 Empirical Formula:
CaFe2+Si2O6
 Environment:
Contact metasomatic rocks.
 IMA Status:
Approved IMA 1987
 Locality:
Nordmark, Sweden.
 Name Origin:
Named after the Swedish mineralogist, M. A. L. Hedenberg.
Physical Properties:
 Cleavage:
[???] Perfect, [???] Indistinct
 Color:
brownish green, gray green, grayish black, dark green, or black.
 Density:
3.55
 Diaphaniety:
Transparent to translucent to opaque
 Habits:
Granular - Generally occurs as anhedral to subhedral crystals in matrix., Crystalline - Fine - Occurs as well-formed fine sized crystals., Lamellar - Thin laminae producing a lamellar structure.
 Hardness:
5-6 - Between Apatite and Orthoclase
 Luminescence:
Non-fluorescent.
 Luster:
Vitreous - Pearly
 Streak:
white green
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B: (Kimia) hedenbergit
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