Chalcocite, arsenopyrite, chalcopyrite and bornite. Wheal Jane, Cornwall, Britain

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This is the same field of view as previous section but after repolishing. Chalcopyrite (yellow) and bornite (brown) now show their characteristic colours. The alteration of chalcopyrite to bornite and chalcocite has been controlled by grain boundaries, fractures and cleavage directions within chalcopyrite.

Polished block, plane polarized light, x 80, air

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