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Formula: Pb3Cl3(Se4+O3)(OH)
Selenite
Crystal System: Orthorhombic
Specific gravity: 7.63 calculated
Hardness: 3
Streak: White
Colour: Pale yellow-brown
Solubility: Insoluble in water and in hydrochloric acid
Environments
Sedimentary environments
Hydrothermal environments
Guangyuanite is a new mineral, approved in 2023 and to date (March 2024) reported only from the type locality.
Localities
At the type locality, El Dragón mine, Porco Municipality, Antonio Quijarro Province, Potosí, Bolivia,
guangyuanite has been found as equant crystals. Associated minerals are
cobalt-bearing
krut'aite–penroseite,
chalcomenite, schmiederite,
olsacherite, phosgenite,
anglesite, cerussite and
franksousaite
(MM 88.97-104).
The ore mineralisation at El Dragόn is the most spectacular occurrence of
selenium-bearing minerals on Earth known today. Although volumetrically
very minor, a total of 34 selenides,
selenites and selenates have been
detected to date (March 2024). It is the type
locality of 12 selenium mineral species. The minerals occur in small
hydrothermal veins, up to 4 cm thick, cutting Paleozoic (541 to 252 million years ago) sedimentary rocks. The origin of
the selenium veins was multiple injections of highly oxidised, metal-rich
fluids into faults at the interface between black shale and
siltstone. Selenides dominate
over sulphides
(Mindat).
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