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Malachite (Photo) [abbr. Mlc ]

Year of discovery: Prehistoric (World), 1885 (Japan)

Locality list: 424 localities of malachite

• Cu₂CO₃(OH)₂
• [Cu²⁺₂][(OH)₂|CO₃]^4-

• Class: Malachite group
• Class: Carbonate - Hydroxide
• Soluble in: HCl (with bubbles), HNO₃, H₂SO₄
• Dehydrates to Tenorite above 315 degree.
• Alter to Cerussite with Linarite.
• Alter to Azurite or Cuprite.
• Formed by alteration of Teineite.
• Substitution pseudomorph: Replace Atacamite, Azurite, Brochantite, Calcite, Cerussite, Chalcophyllite, Chalcopyrite, Cuprite, Libethenite, or Tetrahedrite-(Fe).
• Substitution pseudomorph: Replaced by Shattuckite or Brochantite.
• Incrustation pseudomorph: Replace Gypsum, Pyrite, or Sphalerite.
• Formed at pH 6.0-8.0. Brochantite is stable less than pH 6.0 and Tenorite is stable more than pH 8.0.
• Malachite is stable at ambient and alkaline conditions. Chalcocite is formed at the more reductive condition, and Azurite is formed at the more oxidizing condition.

• Cu => Fe: Chukanovite
• Cu => Ni: Nullaginite
• Cu => Mg: Pokrovskite
• Cu => (Cu,Ni): Glaukosphaerite
• Cu => (Cu,Zn): Rosasite
• Cu => (Cu,Co): Kolwezite
• Cu => (Mg,Cu): Macguinnessite

• Color: Green
• Streak: Pale green
• Luster: Adamantine
• Diaphaneity: Transparent-Translucent

• Habit: Acicular
• Aggregate: Reniform

• Cleavage: Perfect on {-201} (1 plane), Distinct on {010} (1 plane)
• Hardness: 3.5-4
• Density: 4.0

• System: Monoclinic
• Group: 2/m, P2₁/a
• Lattice: a=9.5, b=12.0, c=3.2, β=98.8

Etymology: Malache (Mallow) in Greek