mineral
Polished malachite slab
Malachite, Cu₂CO₃(OH)₂; likely polished and possibly resin-stabilized
AI-generated identification · may be incorrectVivid emerald-to-blue-green concentric banding, silky to vitreous polish, opaque, and typically monoclinic. Mohs hardness 3.5–4; specific gravity about 3.6–4.0; perfect cleavage, though the pictured piece is shaped rather than naturally crystalline.
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Physical properties
Vivid emerald-to-blue-green concentric banding, silky to vitreous polish, opaque, and typically monoclinic. Mohs hardness 3.5–4; specific gravity about 3.6–4.0; perfect cleavage, though the pictured piece is shaped rather than naturally crystalline.
Formation & geological history
A secondary copper-carbonate mineral formed by weathering and oxidation of copper deposits, commonly replacing or coating copper sulfides in shallow zones. Most gem-quality material comes from the Democratic Republic of Congo, Zambia, Russia, and Australia; geological ages vary by deposit.
Uses & applications
Used for ornamental slabs, carvings, cabochons, jewelry, pigments, and collectibles; its softness makes it unsuitable for heavy-wear applications.
Geological facts
The dramatic concentric patterns are characteristic botryoidal malachite growth. Blue-green areas may include chrysocolla or azurite, so this may be a malachite–chrysocolla composite rather than pure malachite.
Field identification & locations
Identify by green banding, high density, softness, and a green streak; avoid acids, abrasion, heat, and prolonged moisture. Common localities include Katanga, Zambia, the Urals, and Arizona.
