General Information:
Chemical Formula:
MnO2
Composition:
(Molecular Weight = 86.94 gm)
Manganese 63.19 % Mn
Oxygen 36.81 % O
Empirical Formula:
Mn4+O2
Environment:
Manganese deposits with pyrolucite.
Locality:
Lake Valley, Sierra County, New Mexico.
Name Origin:
Named after the American mineralogist, Lewis S. Ramsdell (1895-1975), of the University of Michigan, who first described the mineral.
Physical Properties:
Cleavage:
[???] Good
Color:
iron black, black, or steel gray.
Density:
4.37
Diaphaniety:
Opaque
Habits:
Massive - Fibrous - Distinctly fibrous fine-grained forms., Granular - Generally occurs as anhedral to subhedral crystals in matrix., Platy - Sheet forms (e.g. micas).
Hardness:
3 - Calcite
Luster:
Metallic
Streak:
brownish black
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