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Annite (Photo) [abbr. Ann ]

Year of discovery: 1868 (Cape Ann, USA), 1898 (Japan)

Locality list: 118 localities of annite

• KFe₃AlSi₃O₁₀(OH)₂
• KFe₃AlSi₃O₁₀(OH,F)₂
• [K⁺][Fe²⁺₃][(OH)₂|AlSi₃O₁₀]^7-

• Class: Biotite series < Trioctahedral < True mica group < Mica supergroup
• Class: Phyllosilicate - Hydroxide
• Electrical: Electrostatic (Rubbed, Positive)
• Radioactive: Very weak

• Fe => Mg: Phlogopite
• Fe => Mn: Shirozulite
• Fe => Zn: Hendricksite

• Al => Fe³⁺: Tetraferriannite

• OH => F: Fluorannite

• Fe²⁺₃ => Al³⁺₂: Muscovite

• Color: Black
• Streak: Pale brown
• Luster: Adamantine
• Diaphaneity: Translucent-Opaque

• Habit: Hexagonal platy

• Cleavage: Perfect (1 plane)
• Hardness: 3
• Density: 2.8

• System: Monoclinic (1M) (Layer-stacking polytype)
• Group: 2/m, C2/m
• Lattice: a=5.4, b=9.3, c=10.3, β=100.0