Altisite

Formula:  Na₃K₆Ti₂Al₂Si₈O₂₆Cl₃

Origin of name: Name for the elements Al, Ti, and Si in the composition.

Crystal system:  Monoclinic

Crystal class:  2/m

Twinning:

Unit cell: a = 10.37 Å, b = 16.32 Å, c = 9.16 Å, b = 105.6°

Colour: Colourless to white

Diaphaneity: Transparent

Luster: Vitreous

Habit: Anhedral Grains, granular without the expression of crystal shapes

Hardness:  6

Specific gravity:  2.64

Cleavage:  

Tenacity: Brittle

Streak:  White

Synonyms/varieties:

Comments: In the interstices of pectolite crystals in a hyperagpaitic pegmatite.