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Formula: (Cu,Ca,Fe)10Bi(AsO4)4(OH)11.2H2O
Arsenate, bismuth-bearing mineral
Crystal System: Tetragonal
Specific gravity: 3.61 measured, 3.56 calculated
Hardness: 1
Streak: Greenish yellow
Colour: Yellow-green, olive-green
Luminescence: No fluorescence under UV
Environments
Localities
From the Lower dumps, North Star Mine, Mammoth, Tintic Mining District, Juab County, Utah, USA, a specimen showing
green tetragonal plates of juanitaite with azurite,
mixite and baryte was found to be
compositionally zoned, with one end being mixite and the other end being
juanitaite. Most of the single crystals do not exceed 0.1 mm in width
(MinRec 33.2.208)
Juanitaite from the Lower Dumps - Image
At the type locality, the Gold Hill Mine, Gold Hill, Gold Hill Mining District, Tooele County, Utah, USA, the
juanitaite from the 30-foot level is found coating surfaces and filling thin fractures in
gossan. It is associated with calcium-rich
mixite, conichalcite,
chrysocolla, azurite,
gold and quartz. It has also been
found in quartz veins on the 150-foot level, forming fine-grained coatings
on cavity walls, and is associated with connellite,
tyrolite and azurite.
Juanitaite crystals are square crystal plates, 25 to 150 microns across and 1 micron thick, with rounded
corners. Sheaf-like subparallel aggregates and rosettes are scattered over fracture surfaces. Juanitaite
originated from the oxidation of tennantite,
chalcopyrite and pyrite in
quartz veins, and consequent fluid remobilisation of ions
(MinRec 31.301-305).
Juanitaite from the Gold Hill Mine - Image
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