Lepidolite (KLi₂Al(Al,Si)₃O₁₀(F,OH)₂) is a lilac or rose-violet colored phyllosilicate mineral of the mica group that is a secondary source of lithium. It is associated with other lithium-bearing minerals like spodumene in pegmatite bodies.

Physical Properties

Color: violet to pale pink to white, sometimes gray or yellow.

Luster: vitreous to pearly.

Transparency: transparent to translucent.

Crystal System: monoclinic; 2/m.

Crystal Habits: include tabular to prismatic crystals with a prominent pinacoid termination. Lepidolite forms pseudo-hexagonal "books." Also as micaceous or granular masses.

Cleavage: perfect in one direction perpendicular to the c-axis.

Fracture: uneven.

Hardness: 2.5

Specific Gravity: 2.8+

Streak: white

Associated Minerals: quartz, feldspar, spodumene, amblygonite, tourmaline.

Notable Occurrences: Brazil; Ural Mountains, Russia; California.

Reference

"Manual of Mineralogy, 20th Ed." by Cornelius Hurlbut and Cornelis Klein

See also: List of minerals