(por'-phyry cop'-per de-pos'-it) A large body of rock, typically a porphyry (an igneous rocks that contains larger crystals in a fine-grained groundmass or matrix), that contains disseminated chalcopyrite and other sulfide minerals. Such deposits are mined in bulk on a large scale, generally in open pits, for copper and byproduct molybdenum. Most deposits are 3 to 8 km across, and of low grade (less than 1% Cu). They are always associated with intermediate to felsic hypabyssal porphyritic intrusive rocks. Distribution of sulfide minerals changes outward from dissemination to veinlets and veins. Supergene enrichment has been very important at most deposits, as without it the grade would be too low to permit mining.

A crystallized rock, typically porphyritic, having hairline fractures that contain copper and other metals.

a valuable copper-rich deposit in which copper minerals occur throughout the rock