General Information:
Chemical Formula:
Mn++2Al3(SiO4)(Si2O7)(OH)3
Composition:
(Molecular Weight = 502.09 gm)
Manganese 21.88 % Mn
Aluminum 16.12 % Al
Silicon 16.78 % Si
Hydrogen 0.60 % H
Oxygen 44.61 % O
Empirical Formula:
Mn2+2Al3(SiO4)(Si2O7)(OH)3
Environment:
Metamorphosed manganese deposit.
Locality:
Val d'Eff, grisons, Switzerland.
Physical Properties:
Cleavage:
[101] Distinct
Color:
deep reddish brown or copper red.
Density:
3.256
Diaphaniety:
Transparent to translucent
Habits:
Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite), Botryoidal - "Grape-like" rounded forms (e.g.. malachite).,
Luster:
Vitreous (Glassy)
Streak:
yellowish brown
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