Ericssonite

General Information:
 Chemical Formula:
BaMn++2Fe+++O[Si2O7](OH)
 Composition:
(Molecular Weight = 504.22 gm)
Barium 27.24 % Ba
Manganese 21.79 % Mn
Iron 11.08 % Fe
Silicon 11.14 % Si
Hydrogen 0.20 % H 
Oxygen 28.56 % O 
 Empirical Formula:
BaMn2+2Fe3+Si2O8(OH)
 Environment:
Intergrown with orthoericssonite in a schefferite-rhodonite-tephroite skarn.
 IMA Status:
Approved IMA 1968
 Locality:
Langban mine, near Filipstad, Varmland, Sweden.
 Name Origin:
Named for John E. Ericsson (1803-1883), Swedish-born American engineer and inventor, desighner of the iron-clad ship Monitor.
Physical Properties:
 Cleavage:
[100] Perfect, [011] Distinct
 Color:
reddish black.
 Density:
4.21
 Diaphaniety:
Translucent to Opaque
 Habits:
Massive - Uniformly indistinguishable crystals forming large masses., Platy - Sheet forms (e.g. micas).,
 Hardness:
4.5 - Between Fluorite and Apatite
 Luster:
Sub Metallic
 Streak:
brown
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