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Formula: Pb3(WO4)OCl2
Oxychloride, tungsten-bearing mineral
Crystal System: Orthorhombic
Specific gravity: 7.78 calculated
Colour: Bright yellow, golden, orange, pale yellow
Luminescence: No discernable fluorescence under UV
Environments
Localities
At the type locality, the Mammoth-Saint Anthony Mine, St. Anthony deposit, Tiger, Mammoth Mining District, Pinal
County, Arizona, USA, pinalite is a late-stage
secondary mineral found in small cavities in a fine-grained
crystalline quartz matrix. These irregular cavities are
pseudomorphic casts after an uncertain precursor mineral, perhaps
calcite. Pinalite is usually isolated within a cavity or is
associated with and sometimes enclosed by a pale yellow chromium-bearing
leadhillite. Other
secondary minerals occurring in these cavities include
cerussite, matlockite,
diaboleite, caledonite,
connellite, and very rare
iranite, murdochite and
fluorite.
The pinalite occurs as acicular, bladed crystals up to 0.03 x 0.01 x 0.2 mm3; it forms isolated
crystals, but more commonly forms slightly divergent sprays
(AM 74.934-935).
Pinalite from the Mammoth-Saint Anthony Mine -
Image
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