Detailed information
Species
Bornite, Tennantite
Dimensions
105 x 83 x 60
mm
Locality
Carn Brea Mine Camborne, Illogan Cornwall, England
Condition
No recorded repairs
Well-crystallized Bornite is not common, especially from Cornwall, making this dense cabinet specimen a fine example. It is clearly a very old specimen as demonstrated by a large (10.6 x 7.8 cm) and very fine accompanying German printed and handwritten label from the Joanneum Institution in Graz, Austria whose collection was catalogued in 1855. Its original label simply records it as from "Cornwall, England", but it has later been documented as from Carn Brea mine at Camborne/Illogan. This mine lay a little north of Carn Brea, a granite offshoot of the Carnmenellis granite, close by the main railway line and A30 Camborne-Redruth road. The iron-stained granitic matrix is richly coated with dark blue-grey Bornite crystals and sharper, silvery grey metallic Tennantite crystals, lining its vuggy upper surface. This combination of Bornite and Tennantite is quite unusual. The Bornite crystals appear almost cubic with interpenetrant growth and are coloured pinchbeck-bronze grading to tarnished bluish black. There is minor cracking within the specimen, but it appears to be stable. Glued to the base of the specimen are no less than five paper catalogue labels (all neat and tidy) plus an inked-on number. Ex Professor Werner Paar collection.