Bornite Bornite Bornite, also known as peacock ore, is a sulfide mineral with chemical composition CuFeS that crystallizes in the orthorhombic system (pseudo-cubic). Bornite has a brown to copper-red color on fresh surfaces that tarnishes to various iridescent shades of blue to purple in places. Its striking iridescence gives it the nickname "peacock copper" or "peacock ore". Bornite is an important copper ore mineral and occurs widely in porphyry copper deposits along with the more common chalcopyrite. Chalcopyrite and bornite are both typically replaced by chalcocite and covellite in the supergene enrichment zone of copper deposits. Bornite is also found as
Neuil mine by sphalerite, pyrite and chalcopyrite. The ore therefore belongs to the mineralisation type "sphalerite-pyrite-galena-chalcopyrite". A radiometric lead isotope study on the basement lodes yielded an age of 300 to 250 million years BP (Lougnon, J. et al. 1974). The lodes belong clearly to a late Variscan phase and were definitely formed after the intrusion of the Piégut-Pluviers Granodiorite into the paragneisses during the late Pennsylvanian (elsewhere lodes can be found that also formed within the granodiorite). Yet the metal impregnation is most likely genetically related to the granodiorite. The spatial arrangement of the lodes points towards local southeasterly extension within