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Brochantite (Photo)

Year of discovery: 1824 (Mednorudyanskoye deposit, Russia), 1901 (Japan)

Locality list: 76 localities of brochantite

• Cu₄(SO₄)(OH)₆
• [Cu²⁺₄][(OH)₆|SO₄]^8-

• Class: Sulfate - Hydroxide
• Soluble in: HCl, HNO₃, H₂SO₄
• Alter to Chrysocolla.
• Formed by alteration of Langite or Wroewolfeite.
• Substitution pseudomorph: Replace Malachite, Azurite, or Langite.
• Substitution pseudomorph: Replaced by Malachite.
• Stable at ambient temperature. Antlerite is formed stably under higher temperature (60-80 degree).
• Formed at pH 5.0-6.0. Antlerite is stable less than pH 5.0 and Malachite is stable more than pH 6.0.
• Chalcocite is formed at the more reductive condition.

• Color: Green
• Streak: Pale green
• Luster: Vitreous
• Diaphaneity: Transparent, Translucent

• Habit: Long prismatic

• Cleavage: Perfect on {100} (1 plane)
• Hardness: 3.5-4
• Density: 4.0

• System: Monoclinic (MDO1), Monoclinic (MDO2) (Order-Disorder polytype)
• Group: 2/m, P2₁/a
• Lattice: a=13.1, b=9.9, c=6.0, β=103.4

Etymology: A.J.F.M.Brochant, French geologist