Galena 1–2% silver, a byproduct that far outweighs the main lead ore in revenue. Galena deposits often also contain significant amounts of silver as included silver sulfide mineral phases or as limited solid solution within the galena structure. These argentiferous galenas have long been the most important ore of silver. Galena deposits are found worldwide in various environments. Noted deposits include those at Freiberg in Saxony; Cornwall, the Mendips in Somerset, Derbyshire, and Cumberland in England; the Madan and Rhodope Mountains in Bulgaria; the Sullivan Mine of British Columbia; Broken Hill and Mount Isa in Australia; and the ancient mines of
Iron oxide copper gold ore deposits named as IOCG, by discovery and study of the supergiant Olympic Dam copper-gold-uranium deposit, and South American examples. IOCG deposits are classified as separate to other large intrusive related copper deposits such as porphyry copper deposits and other porphyry metal deposits primarily by their substantial accumulations of iron oxide minerals, association with felsic-intermediate type intrusives (Na-Ca rich granitoids), and lack of the complex zonation in alteration mineral assemblies commonly associated with porphyry deposits. The relatively simple copper-gold +/- uranium ore assemblage is also distinct from the wide spectrum of Cu-Au-Ag-Mo-W-Bi porphyry deposits, and there is often no metal zonation within