Grischunite

minerals

sarkinite

brandtite

berzeliite

Formula: NaCa2Mn2+5Fe3+(AsO4)6.2H2O
Hydrated normal arsenate, wicksite group
Specific gravity: 3.8
Hardness: 5
Streak: Brown
Colour: Dark red-brown
Environments

Metamorphic environments

Grischunite is a rare arsenate found only at its type locality to date (March 2021).

Localities

At the type locality, Falotta, Tinizong, Oberhalbstein, Albula Valley, Grisons, Switzerland, grischunite occurs as an alteration product of sarkinite, with which it is intimately intergrown, in a manganese deposit. Associated minerals include sarkinite, brandtite, manganoan berzeliite, tilasite, rhodochrosite and braunite (AM 71: 227-228).

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