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Shigaite

Year of discovery: 1985 (Japan as the first occurence in the World)

Locality list: 2 localities of shigaite

• NaMn₆Al₃(SO₄)₂(OH)₁₈,12H₂O
• [Na(H₂O)₆][Mn²⁺₆][Al³⁺₃][(OH)₁₈|(SO₄)₂]^22-,6H₂O

• Class: Wermlandite group < Hydrotalcite supergroup
• Class: Sulfate - Hydroxide - Hydrate

• Mn => Fe: Nikischerite

• Color: Pale yellow, Brown
• Streak: Pale yellow
• Luster: Vitreous
• Diaphaneity: Transparent

• Habit: Hexagonal platy

• Cleavage: Perfect on {0001} (1 planes)
• Hardness: 2
• Density: 2.3

• System: Trigonal
• Group: (-3), R(-3)
• Lattice: a=9.5, c=32.8

Etymology: Shiga prefecture, Japan, the address of Ioi mine where this mineral was discovered for the first time.