Malachite - Cu₂CO₃(OH)₂

Habit: Bright green, with crystals deeper shades of green or very dark to nearly black. Crystals uncommon, usually short or long prismatic or acicular, often in rosettes, sprays or tufts; botryoidal to mammillary aggregates of radiating fibrous crystals more common; also massive, compact or stalactic. Adamantine to vitreous luster, silky if fibrous or dull to earthy if massive; transparent to translucent. Light green streak.

Environment: A common secondary mineral formed in the oxidation zone of copper deposits.

Etymology: Named in antiquity after the Greek word for mallows, alluding to the similarity of the mineral’s green color to that of mallow leaves.

Malachite is a minor ore of copper but is mainly employed as an ornamental material or cut to make gemstones. It has also been used as a green artist’s pigment and as a cosmetic, from as early as 3000 bce.