[ Top ] [ Japanese ]

Illite series [abbr. Ilt ]

Year of discovery: 1949 (Japan)

Locality list: 254 localities of illite

• K_0.65Al₂(Al_0.65,Si_3.35)O₁₀(OH)₂
• (K,H₃O)(Al,Mg,Fe)₂(Si,Al)₄O₁₀(H₂O,OH)₂
• [K⁺_0.65][Al³⁺₂][][(OH)₂|Al_0.65Si_3.35O₁₀]^6.65-
• A series name of several end-member minerals which have not defined yet.

• Class: Trioctahedral < Interlayer-deficient mica group - Mica supergroup
• Class: Phyllo-Aluminosilicate - Hydroxide
• Comments: Radioactive (Very weak)

• Color: White
• Streak: White
• Luster: No

• Habit: Earthy

• Cleavage: Perfect (1 plane)
• Hardness: 1.5
• Density: 2.9

• System: Monoclinic (1M, Low temperature), Monoclinic (1Md, Low temperature), Monoclinic (2M₁, Low-Moderate temperature) (Layer-stacking polytype)
• Group: 2/m, C2/m
• Lattice: a=5.2, b=9.0, c=10.0, β=94.9