Chalcopyrite copper during hydrothermal circulation. Chalcopyrite is concentrated in this environment via fluid transport. Porphyry copper ore deposits are formed by concentration of copper within a granite stock during the ascent and crystallisation of a magma. Chalcopyrite in this environment is produced by concentration within a magmatic system. Chalcopyrite is an accessory mineral in Kambalda type komatiitic nickel ore deposits, formed from an immiscible sulfide liquid in sulfide-saturated ultramafic lavas. In this environment chalcopyrite is formed by a sulfide liquid stripping copper from an immiscible silicate liquid. Chalcopyrite is the most important copper ore. Chalcopyrite ore occurs in a variety of
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