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Sadanagaite [abbr. Sdg, Msdg ]

Year of discovery: 1996 (Japan as the first occurence in the World)

Locality list: 2 localities of sadanagaite

• NaCa₂Mg₃Al₅Si₅O₂₂(OH)₂
• NaCa₂Mg₃(Al,Fe)₂Al₃Si₅O₂₂(OH)₂
• [Na⁺][Ca²⁺₂][Mg²⁺₃][Al³⁺₂][(OH)₂|Al₃Si₅O₂₂]^17-
• Definition before 1984 was K>Na and/or Fe>Al, and before 2012 was Fe>Mg.

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

• Na => K: Potassic-sadanagaite (Series)

• Mg => Fe: Ferro-sadanagaite

• CaAl => NaSi => Taramite

• Al₂ => Fe₂: Ferri-sadanagaite

• NaAl => []Si: Tschermakite

• Al₂ => MgSi: Pargasite

• Al₄ => Mg₂Si₂: Edenite

• Color: Black, Dark brown
• Streak: Pale brown
• Luster: Vitreous
• Diaphaneity: Translucent

• Habit: Acicular, Prismatic

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

• System: Monoclinic
• Group: 2/m, C2/m
• Lattice (2009): a=9.9, b=17.9, c=5.3, β=105.4

Synonym: Magnesiosadanagaite