Kenhsuite

kenhsuite

montmorillonite

cinnabar

corderoite

Images

Formula: Hg3S2Cl2
Sulphide of mercury, orthorhombic paramorph of isometric corderoite and monoclinic lavrentievite
Crystal System: Orthorhombic
Specific gravity: 6.87 calculated
Hardness: 2 to 3
Streak: Canary yellow
Colour: Canary yellow when fresh, but photosensitive and blackens within a few minutes on exposure to direct sunlight
Luminescence: Fluoresces red to red-orange under long-wave UV (366 nm); the fluorescence weakens for samples exposed to sunlight
Environments

Hydrothermal environments

Localities

At the type locality, the McDermitt mine, Opalite Mining District, Humboldt county, Nevada, USA, kenhsuite is found in hydrothermally altered rhyolitic, tuffaceous lacustrine (formed in lakes) rocks. Regionally, the rocks have become altered to diagenetic alkaline zeolite minerals and, locally, to hydrothermal montmorillonite, kaolinite, adularia, opal and cristobalite.
Kenhsuite was found at one location near the centre of the open pit, in montmorillonite and associated with cinnabar and corderoite. Rare mercury-bearing minerals that also occur at McDermitt include radtkeite, calomel, kleinite, eglestonite, native mercury and possibly mosesite. Extremely fine grains of kenhsuite, with coarser cinnabar and corderoite, are dispersed in clay adjacent to fractures in argillised tuffaceous sedimentary rocks. Fibrous and bladed crystals 1 x 10 microns in length are typical.
Pyrite and stibnite were deposited earlier than cinnabar, which preceded the mercury sulpho-halide minerals. Corderoite, which accounts for approximately 25% of the mercury ore, formed by the reaction of sulphur-deficient chloride solutions with cinnabar, by means of a volume-for-volume replacement. Kenhsuite commonly is in contact with both cinnabar and corderoite, Some kenhsuite also occurs as isolated masses and individual crystals on fracture surfaces and cavities, near cinnabar and corderoite (CM 36.201-206).

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