Bournonite

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Bournonite, 10.1 cm, from the Machacamarca district, Cornelio Saavedra Province, Potosí, Bolivia. These unusual bournonite cogwheels are from a recently discovered occurrence in the district (not the Viboras mine) discovered around 2019. Tom Spann photo.

Product details

SpeciesBournonite
SizeCabinet
Dimensions10.1 cm
Added on02/13/2026
Publications
  • Mineralogical Record Mineral Collecting In Texas page 228
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Bournonite
Mineral guide
Learn about Bournonite
steel-gray to black sulfosalt famed for cogwheel twinning and metallic luster; prized by collectors for iconic gears and historic localities.
Bournonite
Regional guide
Bournonite from Machacamarca mining district
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Locality guide
Machacamarca mining district
Machacamarca mining district, Bolivia - premier source of bournonite, with steel-gray cogwheels on quartz and pyrite, prized for locality and rarity.