Corderoite

corderoite

cinnabar

kleinite

kenhsuite

Images

Formula: Hg3S2Cl2
Halide, paramorph of kenhsuite and lavrentievite, mercury-bearing mineral
Specific gravity: 6.845 calculated
Hardness: 3
Colour: Light orange-pink, but becomes light grey to black on prolonged exposure to light
Environments

Volcanic igneous environments
Hydrothermal environments

Localities

At the Arzak Hg occurrence, Uyuk Range, Pi-Khem District, Tuva, Russia, corderoite occurs in the oxidised hydrothermal deposit asssociated with cinnabar, calomel, eglestonite, arzakite, lavrentievite, kuznetsovite, mercury, quartz and kaolinite (HOM).

At the type locality, the McDermitt mine, Opalite Mining District, Humboldt County, Nevada, USA, corderoite, with or without cinnabar, occurs predominantly in playa sediments. The lake sediments consist of clays (altered tuff and ash) with lesser amounts of agglomerate and small lenses of chalcedony. The associated ore zone minerals are mainly pale green to buff-coloured montmorillonite, alpha quartz, cristobalite, K-feldspar and plagioclase feldspar.
Corderoite occurs in this zone as separate masses or as replacements and rims for cinnabar, other associated minerals include kleinite, kenhsuite, radtkeite, montmorillonite, quartz, cristobalite, orthoclase and plagioclase. Corderoite and cinnabar also occur within hydrothermally altered rhyolitic breccia in the main Cordero mine and nearby underground workings and surface pits.
The relative ease with which corderoite is formed under acid conditions, the presence of chlorine ions as a common constituent of hot spring or groundwaters, and the relationships observed in the field suggest that corderoite is a low temperature supergene mineral (AM 59.652-655, HOM).

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