Johannsenite

General Information:
 Chemical Formula:
CaMnSi2O6
 Composition:
(Molecular Weight = 247.18 gm)
Calcium 16.21 % Ca
Manganese 22.23 % Mn
Silicon 22.72 % Si
Oxygen 38.84 % O 
 Empirical Formula:
CaMn2+(Si2O6)
 Environment:
Contact metasomatic rocks.
 IMA Status:
Approved IMA 1987
 Locality:
Empire Zinc Company mine near Hanover, Grant County, New Mexico.
 Name Origin:
Named after Prof. Albert Johannsen of the University of Chicago.
Physical Properties:
 Cleavage:
[110] Good
 Color:
brown, brownish black, greenish, gray, or gray green.
 Density:
3.56
 Diaphaniety:
Translucent to opaque
 Habits:
Acicular - Occurs as needle-like crystals., Massive - Granular - Common texture observed in granite and other igneous rock.,
 Hardness:
6 - Orthoclase
 Luminescence:
Non-fluorescent.
 Luster:
Vitreous (Glassy)
 Streak:
greenish gray
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