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Pyroaurite (Photo)

Year of discovery: 1865 (Långban, Sweden), 1964 (Japan)

Locality list: 17 localities of pyroaurite

• Mg₆Fe₂(CO₃)(OH)₁₆,4H₂O
• [Mg²⁺₆][Fe³⁺₂][(OH)₁₆|CO₃]^18-,4H₂O

• Class: Hydrotalcite group < Hydrotalcite supergroup
• Class: Carbonate - Hydrate - Hydrate
• Formed by alteration of Iowaite.

• Mg => Ni: Reevesite

• Fe => Cr: Stichtite
• Fe => Al: Manasseite, Hydrotalcite
• Fe => Mn: Desautelsite

• Color: Yellow, Brown, White
• Streak: White
• Luster: Vitreous
• Diaphaneity: Transparent

• Habit: Thin platy

• Cleavage: Perfect on {0001} (1 plane)
• Hardness: 2.5
• Density: 2.0

• System: Trigonal (3R), Hexagonal (2H, , Sjögrenite, Sjogrenite) (Layer-stacking polytype)
• Group: (-3)m, R(-3)m
• Lattice: a=3.1, c=23.4

• Coexist: Sjögrenite (Sjogrenite)