Grimselite

grimselite

schrockingerite

baylissite

monohydrocalcite

Images

Formula: K3Na(UO2)(CO3)3.H2O
Hydrated carbonate, uranyl mineral
Crystal system: Hexagonal
Specific gravity: 3.30 measured on synthetic material, 3.27 calculated
Hardness: 2 to 2½
Streak: Light yellow
Colour: Yellow
RADIOACTIVE
Environments

Hydrothermal environments

Localities

At the Rovnost Mine, Jáchymov, Karlovy Vary District, Karlovy Vary Region, Czech Republic, grimselite has been found with čejkaite (Mindat photo).
Grimselite from the Rovnost Mine - Image

At the type locality, the Gerstenegg-Sommerloch tunnel, Gerstenegg, Guttannen, Interlaken-Oberhasli, Bern, Switzerland, grimselite is a secondary mineral occurring as crusts of fine-grained aggregates where granodiorite and aplite granite are cut by fissure veins and mineralised zones. Associated minerals include schröckingerite, baylissite, calcite and monohydrocalcite (AM 58.139, HOM).
Grimselite from the Gerstenegg-Sommerloch tunnel - Image

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