[ Top ] [ Japanese ]

Natroalunite-2c

Year of discovery: 1982 (Japan as the first occurence in the World)

Locality list: 16 localities of natroalunite-2c

• NaAl₃(SO₄)₂(OH)₆
• (Na,Ca[],K)Al₃(SO₄)₂(OH)₆
• [Na⁺][Al³⁺₃][(OH)₆|(SO₄)₂]^10-

• Class: Alunite group < Alunite supergroup
• Class: Sulfate - Hydroxide
• Radioactive: Very weak

• Na => K: Alunite
• Na => Ca_0.5: Huangite
• Na => Ba_0.5: Walthierite
• Na => NH₄: Ammonioalunite

• Color: White
• Streak: White
• Luster: Vitreous
• Diaphaneity: Transparent-Translucent

• Habit: Hexagonal tabular

• Hardness: 3
• Density: 2.8

• System: Trigonal (1c, Natroalunite), Trigonal (2c, Natroalunite-2c) (Unit-cell polytype)
• Group: (-3)m, R(-3)m
• Lattice: a=7.0, c=33.5

Etymology: Eich Minami, (1899-1977), Japanese chemist of Tokyo University

Synonym: Minamiite