Holmquistite

Formula:  []Li₂(Mg,Fe)₃Al₂Si₈O₂₂(OH)₂

Origin of name:  For Per Holmquist, Swedish petrologist

Crystal system:  Orthorhombic

Crystal class:  2/m 2/m 2/m

Twinning: 

Unit cell: 

Colour:  Dark violet to light sky-blue

Diaphaneity:  Transparent to translucent

Luster:  Vitreous

Habit:  Crystals slender prismatic to acicular, may be vertically striated; massive; radiating fibrous aggregates

Hardness:  5 to 6

Specific gravity:  3.13

Cleavage:  4; {110} perfect, {001}, {112} and {113} parting

Tenacity: 

Streak:  White, with blue tinge

Synonyms/varieties:

Comments:  Dimorphous with clinoholmquistite; series with ferroholmquistite