[ Top ] [ Japanese ]

Glaucophane [abbr. Gln ]

Year of discovery: 1845 (Syros island, Greece), 1886 (Japan)

Locality list: 153 localities of glaucophane

• Na₂Mg₃Al₂Si₈O₂₂(OH)₂
• [][Na⁺₂][Mg²⁺₃][Al³⁺₂][(OH)₂|(Si₄O₁₁)₂]^14-

• Class: Na amphibole subgroup < w(OH,F,Cl)-dominant amphibole group < Amphibole supergroup
• Class: Inosilicate (Double chain) - Hydroxide
• Insoluble in: HCl

• Na => Li: Holmquistite

• Mg => Fe: Ferro-glaucophane (Series)

• Al => Fe: Magnesio-riebeckite

• []Al => NaMg: Eckermannnite

• []Si => NaAl: Nybøite (Nyboite)

• Color: Dark blue, Gray
• Streak: Pale gray-Bluish gray
• Luster: Vitreous
• Diaphaneity: Translucent

• Habit: Acicular, Prismatic

• Cleavage: Perfect on {110} (2 planes, 120 degree), Good on {001} (1 plane)
• Hardness: 5-6
• Density: 3.1

• System: Monoclinic
• Group: 2/m, C2/m
• Lattice: a=9.6, b=17.8, c=5.3, β=103.7