10) Economically Important Minerals-II                               G 232

 

Supergene, shallow veins, and hot springs

Sulfides

realgar

AsS

1) hot spring deposits, 2) some gold deposits

orpiment, other arsenic minerals, stibnite

orpiment

As2S3

1) hot spring deposits, 2) some gold deposits

realgar, stibnite, native arsenic, calcite, barite, gypsum

stibnite

Sb2S3

1) hydrothermal veins and replacement deposits, 2) hot spring deposits

orpiment, realgar, cinnabar, galena, sphalerite, pyrite, barite, gold

marcasite

FeS2

1) sulfide veins, 2) replacement in limestones or shale

galena, pyrite, chalcopyrite, calcite, dolomite

covellite

CuS

1) secondary (supergene) mineral in veins or disseminated deposits

bornite, chalcopyrite, chalcocite, enargite

cinnabar

HgS

1) masses in volcanic or sedimentary rocks, 2) in veins, 3) disseminated grains

native mercury, realgar, stibnite, pyrite, marcasite, calcite, quartz, opal

Oxides

cuprite

Cu2O

1) secondary mineral in the oxidized zones of copper deposits

native copper, limonite, and other secondary copper minerals such as malachite, azurite, and chrysocolla

uraninite

UO2

1) granitic pegmatite, 2) veins, 3) sandstone

quartz, K-feldspar, zircon, tourmaline, and monazite in pegmatites; cassiterite, galena, sulfides, and arsenides in veins; quartz and secondary minerals in sandstones

Carbonates

malachite

(mal-uh-kite)

hydrous Cu carbonate

1) secondary copper mineral in ore deposits formed by alteration of Cu oxides and sulfides

azurite, cuprite, native copper, limonite, chrysocolla

azurite

(ayh'-zhur-ight)

hydrous Cu carbonate

1) secondary copper mineral in ore deposits formed by alteration of Cu oxides and sulfides

malachite, cuprite, native copper, limonite, chrysocolla

Phosphates

turquoise

aluminous hydrated Cu phosphate

1) secondary mineral in Al-rich volcanic rocks forming veins, seams, stringers, and crusts

kaolinite, limonite, quartz (chalcedony)

Phyllosilicates

(chrysocolla)

(chris-uh-co'-la)

Cu phyllosilicate

1) oxidized zones of copper deposits

malachite, azurite, cuprite, native copper

chrysocolla is usually amorphous with crude Si4O10 layers, and is thus a mineraloid usually listed with the phyllosilicates, although recent compilations do list it as a true mineral