Hessite

hessite

empressite

altaite

petzite

Images

Formula: Ag2Te
Telluride of silver
Crystal System: Monoclinic
Specific gravity: 8.24 to 8.45 measured, 8.4 calculated
Hardness: 2 to 3
Streak: Black
Colour: Lead-grey, steel-grey
Common impurities: Au,Pb
Environments

Placers
Hydrothermal environments

Hessite is widely distributed in tellurium-rich silver-gold ores (Dana). It occurs in hydrothermal medium- and low-temperature veins, and also in small quantities in some massive pyrite deposits (HOM). It is typically found in precious metal-telluride associations, occurring with gold, bismuth, lead, silver or gold tellurides in quartz-carbonate lodes and stockworks (MW).
Other associated minerals include calaverite, sylvanite, altaite, petzite, empressite, rickardite, gold, tellurium, pyrite, galena, tetrahedrite and chalcopyrite (HOM).

Localities

At the Hidden Secret Gold Mine, Golden Mile Mines, Kalgoorlie-Boulder, Kalgoorlie-Boulder Shire, Western Australia, hessite occurred with other tellurides in unusually rich ores of gold (R&M 96.3.207).

At the Con West property, Taseko Lake Area, Clinton Mining Division, British Columbia, Canada, hessite has been found as small grains embedded in chalcopyrite (AM 34.354-356).

At the Pellaire Gold Mines property, Taseko Lake, Clinton Mining Division, British Columbia, Canada, hessite has been found as small grains with native gold (AM 34.354-356).

At the Hedley Monarch Mine, Olalla, Osoyoos Mining Division, British Columbia, Canada, hessite has been found in contact with altaite and petzite (AM 34.354-356).

At the Marble Bay and Little Billie mines, Texada Island, British Columbia, Canada, hessite has been found in minute amounts in close association with chalcopyrite and bornite (AM 34.354-356).

At the Hollinger Mine, Tisdale Township, Porcupine mining district, Timmins area, Cochrane District, Ontario, Canada, hessite has been found as thin films on cleavage planes of ankerite (AM 34.354-356).

At a prospect in Tisdale Township, Porcupine mining district, Timmins area, Cochrane District, Ontario, Canada, a specimen of vein quartz has been found with a small area of hessite and gold at the contact of a serpentine stringer (AM 34.354-356).

At the Hollinger mine, Timmins, Cochrane District, Ontario, Canada, minor specimens of gold and hessite, often associated with petzite, have been collected (R&M 96.3.207).

At the Ardeen Mine, Moss Township, Thunder Bay District, Ontario, Canada, grains of hessite and altaite have been found in a gangue of quartz and calcite; also, hessite has been found together with petzite, as a massive crust on one surface of vein quartz with gold (AM 34.354-356).

At the Kirkland Lake Mine, Kirkland Lake Township, Timiskaming District, Ontario, Canada, hessite has been found as coarsely crystalline calcite with grains of hessite associated with small compact masses of coloradoite, chalcopyrite and tetrahedrite (AM 34.354-356).

Hessite from Kirkland Lake - Image

At the East Sullivan mine, Val d'Or, La Vallée-de-l'Or RCM, Abitibi-Témiscamingue, Quebec, Canada, hessite occurs as disseminated grains in quartz and associated with tourmaline, pyrite, chalcopyrite and gold (AM 34.354-356).

At Burwash Creek, Kluane District, Whitehorse mining district, Yukon, Canada, hessite has been found in a number of small nuggets of gold from the placer workings (AM 34.354-356)

At the Buffalo Hump Group on Mount Stevens, Wheaton River District, Whitehorse mining district, Yukon, Canada, hessite has been found as sparse disseminations in quartz with galena (AM 34.354-356).

At the Emperor Mine, Vatukoula, Tavua Gold Field, Viti Levu, Fiji, hessite occurs with sylvanite and gold (Minrec 39.4.299).

At the Mihara mine, Higashi-Mihara, Ibara City, Okayama Prefecture, Japan, excellent specimens of hessite with gold have been found (R&M 96.3.207).

Hessite from the Mihara Mine - Image

The type locality is the Second Zavodinskii Mine, Zyryan District, East Kazakhstan, Kazakhstan.

Hessite from the Second Zavodinskii Mine - Image

At Botești, Zlatna, Alba, Romania, hessite has been confirmed on a specimen of crystalline sphalerite with a few poorly developed crystals of hessite on a group of compact quartz crystals (AM 34.354-356). It has also been reported from this locality with gold and calcite (R&M 84.6.535).

Hessite from Botești - Image

At the Susuman district, Kolyma River Basin, Magadanskaya Oblast, Russia, good specimens of gold with hessite have been found (R&M 96.3.207).

At Clogau Mine, Bontddu, Gwynedd, Wales, UK, hessite is present in the localised ore-zones where gold and tellurides are present. Samples have been found of hessite associated with tellurobismuthite, tetradymite, galena and chalcopyrite cementing shattered arsenopyrite (MW).

At the Shore Mine, Table Mountain, Vallecito District, Calaveras Coounty, California, USA, hessite occurs sparingly on leaves and sheets of gold (R&M 96.3.207).

At Otto Mountain, Baker, Soda Mountains, Silver Lake Mining District, San Bernardino county, California, USA, primary hessite occurs as tiny blebs either associated with pyrite or galena, or isolated in quartz (R&M 86.2.138).

Hessite from Otto Mountain - Image

At the Crystalline Mine, Jamestown Mine, Jamestown, Jamestown District, Mother Lode Belt, Tuolumne county, California, USA, hessite occurs with sheet gold (R&M 96.3.207).

At the Rex Mine, Gold Hill Mining District, Boulder county, Colorado, USA, gold occurred in small vugs in hessite associated with petzite and coloradoite (R&M 96.3.207).

Hessite from the Rex Mine - Image

At the Cripple Creek mining district, Colorado, USA, hessite has been found as microscopic grains in calaverite (Minrec 36.2.173).

Hessite from Cripple Creek - Image

At the Sunnyside Mine, Browns Hole Area, San Juan county, Utah, USA, hessite is found occasionally with gold (R&M 96.3.207).

At the Tintic Mining District, East Tintic Mountains, Utah, USA, small specimens of gold with hessite have been collected (R&M 96.3.207).
Abundant amounts of hessite have been found in veins and as metallic masses in several mines in the district, the most important being the Trixie mine. So far (2024), it has been reported only from mines in the eastern part of the district, including the Trixie, Tintic Standard, North Lily and Eureka Standard mines.
At the Trixie mine, hessite occurs in veins as black-grey masses and blebs in a matrix of quartz and baryte, and it is frequently found with considerable amounts of gold embedded in and around the hessite.
At the Tintic Standard, Eureka Standard and North Lily mines, hessite occurs as black masses in a matrix of quartz, sometimes also associated with gold. Crystals of hessite to 1 mm, usually associated with gold but sometimes alone, have been found in vugs of quartz at the Trixie mine; veins and masses of hessite can cover many square centimeters on matrix (MinRec 55.2.206).

Hessite from Tintic - Image

At the Daniel's Mine, Virgilina District, Charlotte county, Virginia, USA, hessite occurs with gold and a suite of copper minerals (R&M 96.3.207).

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