Rock Identifier
Lepidolite (Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)) — mineral
mineral

Lepidolite

Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)

Hardness: 2.5–3 on Mohs scale; Color: Pink, lilac, or purple; Luster: Pearly to vitreous; Crystal Structure: Monoclinic; Cleavage: Perfect basal (peels into flakes); Specific Gravity: 2.8–2.9.

Hardness
2
Color
Pink, lilac, or purple
Luster
Pearly to vitreous
Identified More mineral

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Physical properties

Hardness: 2.5–3 on Mohs scale; Color: Pink, lilac, or purple; Luster: Pearly to vitreous; Crystal Structure: Monoclinic; Cleavage: Perfect basal (peels into flakes); Specific Gravity: 2.8–2.9.

Formation & geological history

Forms in granite pegmatites as a product of late-stage magmatic crystallization. Often found with other lithium minerals like spodumene and tourmaline. Widely varied geological ages but typically associated with stabilized continental cratons.

Uses & applications

Secondary source of lithium; used in glass and ceramic production to increase heat resistance; prized as a lapidary material for cabochons and as decorative specimens for collectors.

Geological facts

Lepidolite is one of the major sources of the rare alkali metals rubidium and caesium. It was originally named 'lilalite' because of its lavender color before being renamed after the Greek word 'lepidos' for scale.

Field identification & locations

Identify by its characteristic lilac-pink color and micaceous habit (it can be flaked off with a fingernail). Found commonly in Brazil, Canada (Tanco Mine), Madagascar, and the United States (California, Maine). Collectors should look for vibrant purple hues.