Altisite

Altisite is an exceedingly rare alkaline titanium aluminosilicate chloride mineral with formula [Na₃ K₆ Ti₂ Al₂ Si₈ O₂₆ Cl₃], from alkaline pegmatites. It is a monoclinic-prismatic white mineral containing aluminum, chlorine, oxygen, potassium, silicon, sodium, and titanium.

It’s named after its composition (Aluminum, Titanium, and Silicon).

General information:

Formula: [Na₃ K₆ Ti₂ Al₂ Si₈ O₂₆ Cl₃]
Color: Colorless
Lustre: Vitreous
Hardness: 6
Crystal System: Monoclinic.

Physical Properties of Altisite

The structure consists of (001) aluminosilicate tetrahedral slabs built up by the pentamer- where an aluminum tetrahedron shares its corners with four silicon tetrahedra. These slabs are connected by Ti octahedra and the resulting framework is crossed by three sets of infinite channels which contain the alkali atoms.

Lustre: Vitreous
Streak: White
Hardness: 6 on Mohs scale
Cleavage: None
Density: 2.64 – 2.67, Average = 2.65
Diaphaneity: Transparent
Fracture: Brittle – Conchoidal – Very brittle fracture producing small, conchoidal fragments.
Habit: Anhedral Grains – Granular minerals without the expression of crystal shapes
Luminescence: Non-fluorescent.

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