Bracewellite

bracewellite

eskolaite

guyanaite

mcconnellite

Images

Formula: CrO(OH)
Oxide-hydroxide, diaspore group, paramorph of grimaldiite and guyanaite, chromium-bearing mineral
Specific gravity: 4.45 to 4.48
Hardness: 5½ to 6½
Streak: Dark brown
Colour: Deep red to black
Environments

Sedimentary environments
Hydrothermal environments

Localities

At the type locality, the Merume river, Kamakusa, Potaro-Siparuni Region, Guyana, bracewellite occurs in an alluvial placer deposit, in fine-grained intergrowth with other chromium oxide-hydroxide minerals. Associated minerals include quartz, pyrophyllite, mcconnellite, guyanaite, grimaldiite, gold, gahnite and eskolaite (Mindat).

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