Altisite

Altisite (IMA symbol: Ati^[1]) is an exceedingly rare alkaline titanium aluminosilicate chloride mineral with formula Na₃K₆Ti₂Al₂Si₈O₂₆Cl₃, from alkaline pegmatites. It is named after its composition (ALuminium, TItanium, and SIlicon).^[2][3][4]

Altisite
General
Category	Minerals
Formula	Na3K6Ti2Al2Si8O26Cl3
IMA symbol	Ati
Identification
Color	Colourless
Cleavage	None Observed
Fracture	Conchoidal
Mohs scale hardness	6
Luster	Vitreous
Streak	White
Specific gravity	2.64

The mineral crystallizes in the monoclinic crystal system with space group C2/m.^[2]