Feitknechtite

General Information:
 Chemical Formula:
beta-Mn+++O(OH)
 Composition:
(Molecular Weight = 87.94 gm)
Manganese 62.47 % Mn
Hydrogen 1.15 % H 
Oxygen 36.39 % O 
 Empirical Formula:
Mn3+O(OH)
 Environment:
Alteration product of Mn ores.
 IMA Status:
Approved IMA 1966
 Locality:
Franklin, Sussex County, New Jersey, USA.
 Name Origin:
Named for Walter Feitknecht (1899-1975), Swiss, professor of chemistry, University of Bern.
Physical Properties:
 Color:
brownish black or black.
 Density:
3.8
 Diaphaniety:
Translucent to Subopaque
 Habits:
Thin - Flat dimensioned crystals., Hexagonal - Six-sided crystal shape in cross-section or habit., Platy - Sheet forms (e.g. micas).
 Luster:
Earthy (Dull)
 Streak:
brown
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