[ Top ] [ Japanese ]

Cookeite

Year of discovery: 1866 (Mount Rubellite quarry, USA, and Mount Mica mine, USA), 1967 (Japan)

Locality list: 2 localities of cookeite

• LiAl₅Si₃O₁₀(OH)₈
• (Al,Li)₃Al₂(AlSi₃)O₁₀(OH)₈
• [Li⁺][Al³⁺₄][(OH)₈|AlSi₃O₁₀]^13-

• Class: Chlorite group
• Class: Phyllosilicate - Hydroxide
• Insoluble in: HCl
• Fluorescence: UV excitation (Pale yellow, some examples)

• Color: White, Yellowish green, Brown
• Streak: White
• Luster: Waxy
• Diaphaneity: Translucent

• Cleavage: Perfect on {001} (1 planes)
• Hardness: 2.5-3.5
• Density: 2.7

• System: Monoclinic
• Group: 2/m, P2₁/a
• Lattice: a=5.1, b=8.9, c=14.2, β=98.8