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Potassic-pargasite

Year of discovery: 1994 (Pargas (Parainen), Finland), 1989 (Japan)

Locality list: 4 localities of potassic-pargasite

• KCa₂Mg₄Al₃Si₆O₂₂(OH)₂
• (K,Na)Ca₂(Mg,Fe)₄Al₃Si₆O₂₂(OH)₂
• [K⁺][Ca²⁺₂][Mg²⁺₄][Al³⁺][(OH)₂|(AlSi₃O₁₁)₂]^16-

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

• K => Na: Pargasite

• Mg => Fe: Potassic-ferro-pargasite (Series)

• Al => Fe: Potassic-magnesio-hastingsite

• KMg => []Al: Tschermakite

• KAl => []Si: Magnesio-hornblende

• MgSi => Al₂: Potassic-sadanagaite

• OH => Cl: Potassic-chloro-pargasite
• OH => F: Potassic-fluoro-pargasite

• Color: Black, Brownish black
• Streak: Brownish green
• Luster: Vitreous
• Diaphaneity: Translucent-Opaque

• Cleavage: Perfect on {110} (2 planes, 120 degree)
• Hardness: 6-6.5
• Density: 3.3

• System: Monoclinic
• Group: 2/m, C2/m
• Lattice: a=9.9, b=18.1, c=5.3, β=105.4