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Formula: Cu6Bi(AsO4)3(OH)6.3H2O
Hydrated arsenate with hydroxyl, mixite group
Crystal System: Hexagonal
Specific gravity: 3.79
Hardness: 3 to 4
Streak: Lighter than colour
Colour: Emerald green to blue-green to whitish
Environments:
Mixite is an uncommon secondary mineral in the oxidised zone of bismuth-bearing
copper deposits,
associated with bismutite, skutterudite,
bismuth,
atelestite, erythrite,
malachite and
baryte
(HOM).
Localities
At the type locality, Jáchymov, Bohemia, Czech Republic, mixite occurs with bismutite,
skutterudite and
native bismuth
(Dana, Mindat).
Mixite from Jáchymov - Image
At the St Anton mine and Humbachtal, Wittichen District, Germany, mixite occurs with
erythrite and baryte
(Dana).
At the San Rafael mine, Nye county, Nevada, USA, mixite is associated with
plumbojarosite,
olivenite and kaolinite
(R&M 85.6).
Mixite from San Rafael - Image
At the Tintic Mining District, Juab County, Utah, USA, mixite is somewhat well known, and attractive
specimens have been found at several of the mines, some showing sprays exceeding 1 cm. Mixite from the
district typically occurs on a matrix of quartz or
quartz-baryte, and is commonly
associated with azurite, small white to yellow spheres of
kettnerite and green spheres of
conichalcite. Usually mixite is seen as pale blue to blue-green
sprays of acicular crystals, either singly in vugs or intergrown and covering matrix. Mixite has been found
in the Ajax, Mammoth, Boss Tweed and Carisa mines
(MinRec 55.2.213).
Mixite from Tintic - Image
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