Malachite

Malachite is a green copper carbonate hydroxide, Cu₂CO₃(OH)₂, a hardness 3.5 to 4 mineral that forms in the weathered zones of copper deposits. It often grows in grape-like masses with concentric bands, and it has been used as an ore, a pigment and an ornamental stone.

🪨 Geology Guide Specimen: Open Malachite in the CRV Science Rock & Mineral ID Guide to log the specimen, compare it with the other 8 mineral classes of Dana / Strunz Classes, and test your eye in LithoClade.

When copper sulfides near the surface are weathered by oxygenated, carbonate-bearing water, the copper dissolves and reprecipitates as green carbonates. Malachite forms in this oxidized zone of copper deposits, often with azurite, and it is a useful surface sign of copper below.

Malachite typically forms botryoidal (grape-like) and stalactitic masses with concentric light and dark green bands, produced as layers precipitate one after another. Polished slices give the swirling patterns used in jewelry, boxes and carved columns, as in the famous malachite rooms of Russian palaces.

Malachite is about 57 percent copper and was among the earliest copper ores smelted. Ground malachite was a green pigment in ancient Egypt and in European painting. It fizzes in acid and leaves a pale green streak.

• Azurite — the blue copper carbonate it often forms with
• Copper — the metal it is mined for
• Calcite — another carbonate that fizzes in acid