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Aenigmatite

Year of discovery: 1865 (IIímaussaq complex, Greenland), 1928 (Japan)

Locality list: 4 localities of aenigmatite

• Na₂Fe₅TiSi₆O₂₀
• (Na,Ca)₂(Fe²⁺,Mg,Fe³⁺,Mn²⁺)Ti(Si,Al,Fe³⁺)₆O₂₀
• [Na⁺₂][Fe²⁺₅][Ti⁴⁺][O₂|(SiO₃)₆]^16-

• Class: Aenigmatite group < Sapphirine supergroup
• Class: Inosilicate (Single chain) - Oxide

• Fe²⁺Ti⁴⁺ => Fe³⁺₂: Wilkinsonite

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

• Habit: Prismatic

• Cleavage: Good on {010}, {100} (2 planes)
• Hardness: 5.5
• Density: 3.8

• System: Triclinic, Pseudomonoclinic
• Group: (-1), P(-1)
• Lattice (2009): a=10.4, b=10.8, c=8.9, α=105.1, β=96.6, γ=125.4

Etymology: Aenigma (Riddle) in Greek