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Potassic-ferro-sadanagaite

Year of discovery: 1984 (Japan as the first occurence in the World)

Locality list: 5 localities of potassic-ferro-sadanagaite

• KCa₂Fe₃Al₅Si₅O₂₂(OH)₂
• (K,Na)Ca₂Fe₃(Al,Fe)₂(Si,Al)₈O₂₂(OH)₂
• [K⁺][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
• Radioactive: Very weak

• K => Na: Ferro-sadanagaite

• Fe => Mg: Potassic-sadanagaite (Series)

• Al => Fe: Potassicferroferrisadanagaite

• Al₂ => FeSi: Potassic-ferro-pargasite

• Color: Bluish black
• Streak: Pale brown
• Luster: Vitreous
• Diaphaneity: Translucent

• Habit: Acicular, Prismatic

• Cleavage: Perfect on {110} (2 planes, 120 degree)
• Hardness: 5.5
• Density: 3.3

• System: Monoclinic
• Group: 2/m, C2/m