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Alumohydrocalcite

Year of discovery: 1926 (Potekhina village, Russia), 1972 (Japan)

Locality list: 10 localities of alumohydrocalcite

• CaAl₂(CO₃)₂(OH)₄,3H₂O
• [Ca²⁺][Al³⁺₂][(OH)₄|(CO₃)₂]^8-,3H₂O

• Class: Carbonate - Hydroxide - Hydrate
• Soluble in: boiled Water (Decompose to CaCO₃ and Al(OH)₃), HCl, HNO₃, H₂SO₄
• Variety: Knipovichite (+Cr, Pink)

• 3H₂O => 6H₂O: Para-alumohydrocalcite

• Color: White-Pale yellow
• Streak: White
• Luster: Vitreous
• Diaphaneity: Transparent-Opaque

• Habit: Acicular
• Aggregate: Radial

• Cleavage: Perfect on {100} (1 planes), Imperfect on {010} (1 plane)
• Hardness: 2.5
• Density: 2.2

• System: Triclinic
• Group: (-1), P(-1)
• Lattice: a=6.5, b=14.5, c=5.7, α=95.8, β=93.2, γ=82.2

Etymology: Chemical composition