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Ferro-gedrite (Photo) [abbr. Fgd ]

Year of discovery: 1978 (World), 1957 (Japan)

Locality list: 3 localities of ferro-gedrite

• Fe₅Al₄Si₆O₂₂(OH)₂
• [][Fe²⁺₂][Fe²⁺₃][Al³⁺₂][(OH)₂|(AlSi₃O₁₁)₂]^16-

• Class: Mg-Fe-Mn amphibole subgroup < w(OH,F,Cl)-dominant amphibole group < Amphibole supergroup
• Class: Ino-Aluminosilicate (Double chain) - Hydroxide

• Fe => Mg: Gedrite (Series)

• Al₄ => Fe₂Si₂: Ferro-anthophyllite

• Color: Greenish gray, Brown, Bluish green
• Tarnish: Yellowish brown (Weathering)
• Streak: Gray
• Luster: Vitreous
• Diaphaneity: Transparent-Translucent

• Habit: Prismatic

• Cleavage: Perfect on {110} (2 planes, 120 degree), Indistinct on {010} and {100} (2 planes)
• Hardness: 5.5-6
• Density: 3.6

• System: Orthorhombic
• Group: mmm, Pnma
• Lattice: a=18.5, b=17.9, c=5.3