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Formula: CuPbSbS3
Sulphosalt, bournonite group, forms a series with
seligmannite
Crystal System: Orthorhombic
Specific gravity: 5.83 measured, 5.84 calculated
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:
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, Driggith, Caldbeck, Allerdale, 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 Clargillhead vein, Garrigill, Alston Moor, Eden, Cumbria, England, UK, bournonite is present as discrete
10 to 100 micron diameter masses, in which its characteristic cog-wheel twinning is conspicuous, filling voids within
the radiating quartz gangue. Here it
is intergrown with galena in which bournonite inclusions are present,
and locally accompanies 10 to 20 micron chalcopyrite masses at the
margins of some galena crystals. Bournonite is locally altered to
yarrowite with very rare masses, up to 2 microns across, of probable
enargite
(JRS 23.51).
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 occurs 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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