Description: Bournonite "cogwheel" with Quartz Herodsfoot Mine, Lanreath, Liskeard, Cornwall, England, United Kingdom Specimen size: 5.2 × 2.7 × 3.3 cm Main crystal size: 2.5 × 1.7 cm Mined about 1926 Former collection of Sir Arthur Russell / Former collection of the Folch duplicates Photo: Reference Specimens

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