Lepidolite


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lepidolite

[lə′pid·əl‚īt]
(mineralogy)
K(Li,Al)3(Si,Al)4O10(F,OH)2 A rose-colored mineral of the mica group crystallizing in the monoclinic system. Also known as lithionite; lithium mica.

Lepidolite

 

a mineral of the mica group; by structure, classified as a trioctahedral mica. The approximate chemical composition of lepidolite is KLi1,5 Al1,5 [AlSi3O10] (F, OH), with a Li2O content varying between 1.23 and 5.90 percent. Principal admixtures include Fe2+, Mn, Cs, Rb, and Na. Lepidolite crystallizes in the monoclinic system, forming lamellar crystals and fine-grained scaly masses. The color generally varies from pink to pale violet; colorless varieties are rare. Lepidolite has a hardness of 2.5–3.5 on Mohs’ scale and a density of 2,800–2,900 kg/m3. It occurs in granitic pegmatites in association with pink tourmaline, spodumene, albite, cassiterite, and minerals containing Nb and Ta. Lepidolite is rarely found in greisenized granites and hydrothermal formations. Lepidolite ore is a source of Li and its salts; Cs is sometimes also extracted.

References in periodicals archive ?
The pegmatites consist of feldspars, quartz and lepidolite.
The matrix of these crystals consists essentially of albite and lepidolite.
A few larger and heftier specimens consist of mottled green-pink-blackish elbaite crystals to 4 x 4 x 5 cm with 2-cm lepidolite "books" and smoky quartz crystals attached.
It proved to contain attractive, pastel-red tourmaline crystals with lepidolite and amazonite microcline.
One of these valuable morganite crystals weighs 3 pounds, and when found was covered with crystals of lepidolite.
The adjacent LCT beryl-columbite pegmatites at Morrissey Hill, Beryl Hill and Pyramid Hill only rarely contain lithium minerals such as lepidolite, elbaite and triphylite.
Kosnar assembled an extensive suite of some of the finest kosnarite specimens and also specimens of associated jahnsite, goyazite, quartz, albite and lepidolite.
br) had some microlite specimens found in mid-2004 on the dumps of the Urubu tourmaline mine, Aracuai district, Minas Gerais: yellow-brown, rounded, face-rich crystals to 2 cm, a few of them partly gemmy, perched on pieces of pegmatitic matrix composed chiefly of albite and lepidolite.
Pegmatite-Mine Farm Name Economic Minerals Sandamap Sandamap Cassiterite; ferrotantalite North 115 Cameroon pegmatite Goabeb 63 Cassiterite-equivalent to Sandamap Sidney pegmatite Davib West 62 and Cassiterite; lepidolite northern boundary with Goabeb 63 Borna pegmatite Davib Ost 61 Cassiterite Carsie pegmatite Davib Ost 61 Cassiterite; ferberite; columbite (Fe?
Albite rosettes, tantalite and lepidolite are common as attractive accessory species.
These specimens are certainly nothing on the order of the giant, flaring groups of multicolored prisms which came from the Pederneira mine a few years ago; they are single, loose crystals, a few doubly terminated, many with the distinctive (for Pederneira) brushy clusters of purple subhedral lepidolite books around their bases.