[ Top ] [ Japanese ]

Tobelite

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

Locality list: 4 localities of tobelite

• (NH₄)Al₃Si₃O₁₀(OH)₂
• (NH₄,K)Al₃Si₃O₁₀(OH)₂
• [NH₄⁺][Al³⁺₂][(OH)₂|AlSi₃O₁₀]^7-

• Class: Dioctahedral < True mica group < Mica supergroup
• Class: Ammonium - Phyllo-Aluminosilicate - Hydroxide
• Radioactive: Very weak

• NH₄ => Cs: Nanpingite
• NH₄ => Na: Paragonite
• NH₄ => K: Muscovite

• Color: White, Yellowish green
• Streak: White
• Luster: Vitreous
• Diaphaneity: Translucent

• Habit: Micaceous

• Cleavage: Perfect on {0001} (1 planes)
• Hardness: 2
• Density: 2.6

• System: Monoclinic (1M, 2M₂) (Layer-stacking polytype)
• Group: 2/m, C2/m
• Lattice: a=5.2, b=9.0, c=10.4, β=101.3

• Coexist: Quartz

Etymology: Tobe city in Ehime prefecture, Japan, where this mineral was discovered for the first time.