General Information:
Chemical Formula:
(K,Na,Ca)(Mn,Al)7Si8O20(OH)8·2(H2O) (?)
Environment:
Manganese deposits.
Locality:
Parsettens Alp, Val d'Err, Grisons, Switzerland.
Name Origin:
Named after its locality.
Physical Properties:
Cleavage:
[001] Perfect
Color:
copper red.
Density:
2.59
Diaphaniety:
Translucent to subtranslucent
Habits:
Massive - Lamellar - Distinctly foliated fine-grained forms., Micaceous - Platy texture with "flexible" plates.,
Hardness:
1.5 - Between Talc and Gypsum
Luster:
Vitreous (Glassy)
Streak:
brownish yellow
More details...