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Magnesio-hornblende [abbr. Mhb ]

Year of discovery: 1789 (World as Hornblende), 1895 (Japan)

Locality list: 119 localities of magnesio-hornblende

• Ca₂Mg₄Al₂Si₇O₂₂(OH)₂
• Ca₂Mg₄(Al,Fe)AlSi₇O₂₂(OH)₂₂
• [][Ca²⁺₂][Mg²⁺₄][Al³⁺][(OH)₂|AlSi₇O₂₂]^15-

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

• Ca => Na₂: Katophorite

• Mg => Fe: Ferro-hornblende (Series)

• Al => Fe: Magnesio-ferri-hornblende

• CaMg => NaAl: Barroisite

• []Al => NaMg: Edenite

• CaAl => NaSi: Winchite

• []Si => NaAl: Pargasite
• []Si => KAl: Potassic-pargasite

• Al₂ => MgSi: Tremolite (Series), Actinolite (Series)

• MgSi => Al₂: Tschermakite

• Color: Green, Dark green, Black
• Streak: Gray, Pale green
• Luster: Vitreous
• Diaphaneity: Translucent-Opaque

• Habit: Acicular, Prismatic

• Cleavage: Perfect on {110} (2 planes, 120 degree)
• Hardness: 5-6
• Density: 3.2

• System: Monoclinic
• Group: 2/m, C2/m
• Lattice: a=9.9, b=18.2, c=5.3, β=104.6