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Ferro-sadanagaite

• NaCa₂Fe₃Al₂Al₃Si₅O₂₂(OH)₂
• [Na⁺][Ca²⁺₂][Fe²⁺₃][Al³⁺₂][(OH)₂|Al₃Si₅O₂₂]^17-

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

• Na => K: Potassic-ferro-sadanagaite

• Fe => Mg: Sadanagaite

• Al => Fe: Ferro-ferri-sadanagaite

• NaAl => []Si: Ferro-tschermakite

• CaAl => NaSi: Ferro-taramite

• Al₂ => FeSi: Ferro-pargasite

• Al₄ => Fe₂Si₂: Ferro-edenite

• Color: Bluish black, Dark brown
• Streak: Pale brown
• Luster: Vitreous
• Diaphaneity: Transparent-Translucent

• Habit: Acicular, Prismatic

• Cleavage: Perfect on {110} (2 planes, 120 degree)
• Hardness: 6
• Density: 3.3

• System: Monoclinic
• Group: C2, C2/m
• Lattice: a=9.9, b=18.0, c=5.4, β=105.3