Smithsonite

Real mineral · uncommon · ZnCO₃

Zinc carbonate forming in the oxidised zones of zinc ore deposits. Occurs in a wide range of colours depending on trace impurities. The apple-green variety coloured by copper is among the most prized collector specimens.

Identity

Formula

ZnCO₃

Chemical class

carbonate

Mineral group

Calcite, Rhodochrosite, Siderite

Also known as

Zinc spar, Bonamite (blue-green gem variety)

Crystallography

Crystal system

trigonal

Habits

rhombohedral, botryoidal, massive, earthy

Fracture

subconchoidal

Physical properties

Mohs hardness

4.5

Density

4.45 g/cm³

Luster

vitreous, pearly

Colors

white, gray, green, blue, pink, yellow

Streak

white

Transparency

translucent, opaque

Geology

Origins

sedimentary

Host rocks

zinc ore deposits (oxidized zones), limestone

Associated minerals

Sphalerite, Galena, Hemimorphite, Calcite

Geography

USA, Spain, Greece, Namibia, Mexico

Classification

Rarity

uncommon

Gem quality

Yes

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