mineral
Malachite-bearing matrix specimen
Malachite, Cu₂CO₃(OH)₂, likely with chrysocolla and host rock
AI-generated identification · may be incorrectBright green, botryoidal to crusty aggregates with a vitreous-to-dull luster; Mohs hardness 3.5–4, monoclinic crystal structure, commonly with no obvious cleavage, and specific gravity about 3.6–4.0. The brown-gray matrix may contain limonite, quartz, or chrysocolla.
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Physical properties
Bright green, botryoidal to crusty aggregates with a vitreous-to-dull luster; Mohs hardness 3.5–4, monoclinic crystal structure, commonly with no obvious cleavage, and specific gravity about 3.6–4.0. The brown-gray matrix may contain limonite, quartz, or chrysocolla.
Formation & geological history
Forms as a secondary copper carbonate in the oxidized zones of copper-ore deposits, produced when copper minerals react with oxygenated groundwater and carbonate. It is generally geologically young relative to its host ore, commonly forming during weathering over millions of years.
Uses & applications
Used as a copper ore, ornamental stone, pigment, and collectible mineral; polished malachite is also used in jewelry and decorative objects. Fine banded or vividly colored specimens command the highest prices.
Geological facts
Malachite commonly occurs with azurite, chrysocolla, cuprite, and native copper. Its green streak and reaction with dilute hydrochloric acid help distinguish it from many similar green minerals.
Field identification & locations
Identify by intense emerald-to-dark green color, botryoidal surfaces, moderate softness, green streak, and effervescence in acid; avoid inhaling dust or prolonged contact because copper minerals can be toxic. Common localities include the Democratic Republic of the Congo, Zambia, Russia, Australia, Arizona, and New Mexico.
