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Fluor-dravite

• NaMg₃Al₆(BO₃)₃Si₆O₁₈(OH)₃F
• [Na⁺][Mg²⁺₃][Al³⁺₆][(OH)₃|F|(BO₃)₃|(SiO₃)₆]^25-

• Class: Alkali-subgroup 1 < Alkali-tourmaline group < Tourmaline supergroup
• Class: Cyclosilicate (Single ring) - Borate - Fluoride - Hydroxide

• Mg => Fe: Fluor-schorl
• Mg => Mn: Fluor-tsilaisite

• Mg₂ => LiAl: Fluor-elbaite

• F => OH: Dravite

• NaAl => CaMg: Fluor-uvite (Series)

• MgF => AlO: Oxy-dravite

• Mg₃(OH)₃ => Fe³⁺₃O₃: Fluor-buergerite (Series)

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

• Hardness: 7

• System: Trigonal
• Group: 3m, R3m
• Lattice: a=16.0, c=7.2