General Information:
Chemical Formula:
MnO2
Composition:
(Molecular Weight = 86.94 gm)
Manganese 63.19 % Mn
Oxygen 36.81 % O
Empirical Formula:
Mn4+O2
Environment:
Sedimentary, hydrothermal, and secondary.
IMA Status:
Approved IMA 1967
Locality:
Common world wide.
Name Origin:
From the Greek, pyro and louein, "fire" and "to wash," because it was used to remove the greenish color imparted to glass by iron compounds.
Physical Properties:
Cleavage:
[110] Perfect
Color:
steel gray, iron gray, or bluish gray.
Density:
4.4 - 5.06, Average = 4.73
Diaphaniety:
Opaque
Habits:
Reniform - "Kidney like" in shape (e.g.. hematite)., Dendritic - Branching "tree-like" growths of great complexity (e.g. pyrolusite)., Earthy - Dull, clay-like texture with no visible crystalline affinities, (e.g. howlite).
Hardness:
6-6.5 - Orthoclase-Pyrite
Luminescence:
None.
Luster:
Sub Metallic
Streak:
black
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