Depositional Environments of Group 9 and 10 Minerals

Gold

Quartz veins, placers

Silver

Oxidized zones of ore deposits, hydrothermal veins

Copper

Oxidized portions of copper deposits, primary crystallization from fluids associated with mafic lava

Galena

Common in various sulfide deposits

Sphalerite

Voids within carbonate rocks, hydrothermal veins, contact metamorphic aureoles

Chalcopyrite

Hydrothermal and replacement sulfide deposits, mafic igneous rocks

Chalcocite

Primary/secondary copper ore mineral in veuns and altered zones

Bornite

Sulfide-breaing hydrothermal veins, secondary in enriched zones of sulfide deposits

Molybdenite

Accessory in some granitic rocks and pegmatites, porphyry copper deposits, vein deposits

Arsenopyrite

In veins with other metal ores, in pegmatites, contact aureoles, low-medium grade metamorphic rocks

Realgar

Hot-spring deposits, some gold deposits

Orpiment

Hot spring deposits, some gold deposits

Marcasite

Sulfide veins, replacement in limestone or shale

Cinnabar

Masses in volcanic or sedimentary rocks, in veins, disseminated grains

Uraninite

Granitic pegmatites, veins, sandstone

Malachite and azurite

Secondary copper mineral in ore deposits formed by alteration of Cu oxides and sulfides

Turquoise

Secondary mineral in Al-rich volcanic rocks forming veins, seams, stringers, and crusts

Chrysocolla

Oxidized zones of copper deposits