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Erythrite (Photo)

Year of discovery: 1832 (St Daniel mine, Germany), 1899 (Japan)

Locality list: 27 localities of erythrite

• Co₃(AsO₄)₂,8H₂O
• [Co²⁺₃][(AsO₄)₂]^6-,8H₂O
• [Co(H₂O)₄]²⁺[Co²⁺₂(H₂O)₄]⁴⁺[(AsO₄)₂]^6-

• Class: Vivianite group
• Class: Arsenate - Hydrate
• Soluble in: HCl, HNO₃, H₂SO₄

• Co => Ni: Annabergite (Series)
• Co => Zn: Köttigite (Kottigite) (Series), Metaköttigite (Metakottigite)
• Co => Fe: Symplesite, Parasymplesite
• Co => Mg: Hörnesite (Hornesite) (Series)
• Co => Mn: Manganohörnesite, Manganohornesite

• AsO₄ => PO₄: Pakhomovskyite

• Color: Pink
• Streak: Pale red
• Luster: Vitreous
• Diaphaneity: Transparent-Translucent

• Habit: Earthy, Acicular, Prismatic
• Aggregate: Globular, Reniform

• Cleavage: Perfect on {010} (1 plane), Poor on {100} and {102} (2 planes)
• Hardness: 1.5-2.5
• Density: 3.1

• System: Monoclinic
• Group: 2/m, B2/m
• Lattice: a=10.3, b=13.4, c=4.8, β=105.0

Etymology: Erythro (characteristic red) in Greek