Janggunite

General Information:
 Chemical Formula:
Mn++++5-x(Mn++,Fe+++)1+xO8(OH)6, x = 0,2
 Composition:
(Molecular Weight = 559.85 gm)
Manganese 56.92 % Mn
Iron 2.00 % Fe
Hydrogen 1.08 % H 
Oxygen 40.01 % O 
 Empirical Formula:
Mn4+4.8Mn2+Fe3+0.2O8OH6
 Environment:
In the zone of supergene manganese oxides.
 IMA Status:
Approved IMA 1976
 Locality:
Janggun mine, Bonghwa, Korea.
 Name Origin:
Named for the locality.
Physical Properties:
 Cleavage:
[???] Indistinct
 Color:
black.
 Density:
3.59
 Diaphaniety:
Opaque
 Habits:
Colloform - Forming from a gel or colloidal mass., Dendritic - Branching "tree-like" growths of great complexity (e.g. pyrolusite)., Flakes - Flat, thin crystals or aggregates.
 Hardness:
2-3 - Gypsum-Calcite
 Luster:
Earthy (Dull)
 Streak:
brownish black
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