Images
Formula: UTe4+3O9 is the IMA formula, but a better one is
(U6+O2)Te4+3O7
Tellurite, uranyl mineral
Crystal System: Isometric
Specific gravity: 6.57 measured on synthetic material, 6.77 calculated
Hardness: 4
Streak: Light yellow
Colour: Bright sulphur yellow
RADIOACTIVE
Environments
Cliffordite occurs as rare incrustations along fractures in the oxidised zone of hydrothermal
gold-silver telluride deposits
(HOM).
Localities
At the Moctezuma mine, Moctezuma, Moctezuma Municipality, Sonora, Mexico, cliffordite is associated with
tellurium, paratellurite
and quartz
(HOM).
Cliffordite from the Moctezuma mine -
Image
At the type locality, the San Miguel Mine, Moctezuma, Moctezuma Municipality, Sonora, Mexico, cliffordite
occurs in an environment of andesite
porphyrys and altered
tuffs.
Quartz veins cutting these rocks sometimes contain substantial
amounts of baryte and pyrite, and
locally may be mineralised with native tellurium and other tellurides
including gold and silver minerals.
Oxidation of these veins has given rise to a number of oxidised tellurium minerals, especially
mackayite, besides abundant jarosite
and limonite and other iron oxides coating fractures. Minerals recognised in
very minor amounts include tetrahedrite,
rickardite, emmonsite,
tellurite, schmitterite,
cliffordite and chlorargyrite. The cliffordite is rare and
occurs typically on oxidised joint surfaces in druses and scattered about between larger
mackayite crystals which are thickly disseminated on the same surfaces. The
crystals are always small, up to about 0.2 mm
(AM 54.697-701).
Cliffordite from the San Miguel Mine -
Image
At the San Miguel prospect, Moctezuma, Moctezuma Municipality, Sonora, Mexico, cliffordite is associated with
mackayite, baryte,
quartz and limonite
(HOM).
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