Bournonite

minerals

tetrahedrite

seligmannite

rhodochrosite

Formula: CuPbSbS3
Sulphosalt, bournonite group, forms a series with seligmannite
Specific gravity: 5.83
Hardness: 2½ to 3
Streak: Steel grey
Colour: Steel grey
Solubility: Slightly soluble in nitric acid
Common impurities: As,Ag,Fe,Zn,Mn,Ni
Environments:

Hydrothermal environments

Bournonite is found in mesothermal veins, both as a primary mineral and in the enriched zone. Associated minerals include galena, tetrahedrite, sphalerite, chalcopyrite, pyrite, stibnite, zinkenite, siderite, quartz, rhodochrosite, dolomite and baryte (HOM).

Localities

At the Mount Isa mine, Queensland, Australia, bournonite crystals to 5 cm were found associated with chalcopyrite on quartz - dolomite matrix (R&M 80.1.40-44).

At Machacamarca, Potosí, Bolivia, bournonite has been found in fine twins to 10 cm across, with augelite, tetrahedrite and acanthite (R&M 80.1.40-44).

In the vuggy Tajo vein at Pulacayo, Potosí, Bolivia, at one time magnificent bournonite crystals and twins were common, associated with pyrite, freibergite, pyrargyrite, chalcopyrite, sphalerite and quartz (R&M 80.1.40-44).

In the upper levels of the Cerro Rico vein system at Potosí, Bolivia, bournonite occurred with semseyite, stannite, boulangerite and tetrahedrite (R&M 80.1.40-44).

At Chorolque, Sud Chichas Province, Potosí, Bolivia, bournonite occurs with bismuthinite and galena (R&M 80.1.40-44).

At the Van silver mine, British Columbia, Canada, bournonite generally occurs on quartz, pyrite, sphalerite and galena. A single specimen has been found of a diaphorite crystal overgrown by bournonite (Minrec 31.3.226).

At the Red Lake mine at Balmertown, Ontario, Canada, bournonite occurs in small amounts associated with ores currently producing magnificent gold and berthierite specimens (R&M 80.1.40-44).

At the Tintina silver mines, Tintina, Yukon, Canada, bournonite occurs with owyheeite, tintinaite, and silver-rich tetrahedrite (R&M 80.1.40-44).

At Yaogangxian, China, bournonite occurs in what are probably the world’s largest crystals, up to 10 cm in length. It typically forms in hydrothermal vein systems at intermediate temperatures. Associated minerals include fluorite, quartz, pyrite, galena, sphalerite, chalcopyrite, arsenopyrite, stibnite, boulangerite, zinkenite, tetrahedrite, carbonates, baryte and galenobismutite (R&M 80.1.40-44). Some bournonite crystals have been found wholly covered by boulangerite with 2 mm crystals of chalcopyrite resting on the boulangerite. Pseudomorphs of bournonite after tetrahedrite have been reported (Minrec 42.6.572).

At the Jouchy mine, Isère, Auvergne-Rhône-Alpes, France, bournonite crystals occur on siderite (R&M 80.1.40-44).

At Neudorf, Harzgerode mining district, Harz, Saxony-Anhalt, Germany fine bournonite crystals to 8 cm occur with tetrahedrite; bournonite crystals are also sometimes found associated with galena, chalcopyrite, siderite, and calcite, perched on quartz (Minrec 43.1.29-31).

At Trepca, Kosovo, bournonite crystals are very rare, implanted on galena and pyrite and associated with quartz and carbonates. They are never implanted on sphalerite (Minrec 38.4.281).

At Francisco Portillo in the west camp of Santa Eulalia district, Mexico, crystals of bournonite to 1 cm associated with pyrite and sphalerite have been recovered (R&M 80.1.40-44).

In the Noche Buena mine, Mazapil, and from Conception del Oro, Zacatecas, Mexico, good cogwheel twins to 5 cm across occur with tetrahedrite, pyrite, galena, sphalerite and arsenopyrite (R&M 80.1.40-44).

At Huinac, Ancash department, Peru, bournonite crystals to 2 mm have been found with with crusts of rhodochrosite and tetrahedrite (Minrec 42.2.148).

At Casapalca, Lima, Peru, exceptional crystals of bournonite to 5 cm covering lustrous black sphalerite have been reported (R&M 80.1.40-44).

The type locality is Wheal Boys, Port Isaac, St Endellion, Cornwall, England, UK.

At the Driggith mine, Caldbeck Fells, Cumbria, England, UK, bournonite occurs as grains enclosed by tetrahedrite, and also along cleavages in galena, with chalcopyrite and minor tetrahedrite. Irregular grains of bournonite may occur with native antimony or at chalcopyrite - galena grain boundaries (C&S).

At the Boggs mine in the Big Bug district, Yavapai County, Arizona, USA, bournonite occurred both massive and as crystals with quartz, siderite and other sulphides. (R&M 80.1.40-44).

At the Eagle mine, Gilman district, Eagle County, Colorado, USA, bournonite it occurred as tiny crystals with freibergite, polybasite, stromeyerite and matildite (R&M 80.1.40-44).

At the Keystone mine, Gunnison County, Colorado, USA, bournonite is reported as sharp crystals to 5 mm, on pyrite (R&M 80.1.40-44).

In the North Amethyst vein system at Creede, Mineral County, Colorado, USA, bournonite is associated with acanthite, gold variety electrum, tetrahedrite and other sulphides (R&M 80.1.40-44).

At the Zuni Mine, Anvil Mountain, Red Mountain Mining District, San Juan county, Colorado, USA, arsenic-rich bournonite occurred with pyrite and zunyite (R&M 80.1.40-44).

At the El Paso mine, Cripple Creek mining district, Teller county, Colorado, USA, bournonite has been reported as rims around galena grains and associated with tetrahedrite - tennantite (Minrec 36.2.163).

At the large open-pit silver mine in the Candelaria district, Mineral County, Nevada, USA, bournonite occurred as twinned crystals to 1 cm associated with tetrahedrite, arsenopyrite and boulangerite (R&M 80.1.40-44).

In in the Morey district, Nye County, Nevada, USA, bournonite is found in quartz - rhodochrosite veins (R&M 80.1.40-44).

At the Monitor mine, Taylor district, White Pine County, Nevada, USA, bournonite occurs as excellent single and twinned crystals to 8 mm associated with andorite and enargite in quartz veins (R&M 80.1.40-44).

At the the Mount Hamilton area of the White Pine district, White Pine county, Nevada, USA, bournonite occus with seligmannite (R&M 80.1.40-44).

At the Park City district, Summit County, Utah, USA, crystals reaching several centimeters across and associated with siderite and sphalerite have been found (R&M 80.1.40-44).

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