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The Mineral lepidolite

Lepidolite Flakes

Lepidolite is a lithium-rich mica known for its pink and lilac colors. It is a common matrix mineral to Tourmaline and Quartz, providing them with a very aesthetic and glittery base. A pink variety of the related mica mineral Muscovite can be identical in appearance to Lepidolite, and is many times incorrectly labeled as Lepidolite.

Chemical Formula

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

Color

Pink to purple. Occasionally also light gray and yellow.

Crystal System

Monoclinic

Properties

Streak
White
Hardness
2.5 - 3
Transparency
Transparent to translucent
Specific Gravity
2.8 - 2.9
Luster
Pearly
Cleavage
1,1
Fracture
Uneven
Tenacity
Sectile, Elastic
Other ID Marks
Tendency for small pieces or flakes or peel off.

Crystal Habits

Most often as small, scaly crystals in dense aggregates. Also as micaceous masses and groupings, and in tabular, foliated, flaky, and scaly forms. Large crystals, which are in stubby pseudohexagonal form, are much rarer then the other micas. Also found in micaceous rounded ball-shaped aggregates and in massive form with tiny glittery crystals.

3D Crystal Atlas

Additional Information

Composition
Basic potassium lithium aluminum fluoro-silicate
In Group
Silicates; Phyllosilicates; Mica Group
Striking Features
Flaky habit, crystals, color, sectility, and mode of occurence.
Environment
Lepidolite is restricted to high-lithium granite pegmatites.
Rock Type
Igneous

Other Names

Lithium Mica

Uses

Lepidolite is mined as a source of the element lithium. Fine-grained masses are sometimes polished into ornaments such as eggs and animal carvings.

Noteworthy Localities

Significant Lepidolite specimens come from Afghanistan at Peech, Nangarhar Province; and Paprok, Nuristan Province. Two important African occurrences are Sahatany, Vakinankaratra, Madagascar; and Alto Ligonha, Zambezia, Mozambique. In Europe, very good Lepidolite comes from Varutrask, near Skelleftea, Sweden; and Gonçalo, Guarda, Portugal.

Some of the best examples of Lepidolite come from the gem-bearing pegmatites of Minas Gerais, Brazil. Specific deposits include Aracuai, Coronel Murta, and Virgem da Lapa in the Jequitinhonha valley; and Governador Valadares in the Doce valley. A rare bright yellow form of Lepidolite comes from Itinga in the Jequitinhonha valley.

In the U.S., the rich gem pegmatites of San Diego County, California, have yielded some of the best-known Lepidolite, often associated with valuable Tourmaline. Specific localities include the Stewart Mine at Pala; the Little Three Mine near Ramona; and the Himalaya Mine near Mesa Grande.

Other important U.S. localities are the Gillette Quarry, Haddam, Middlesex Co., Connecticut; the Strickland Quarry, Portland, Middlesex Co., Connecticut; Mt. Apatite, Auburn, Androscoggin Co., Maine; Mount Mica, Paris, Oxford County, Maine; the Black Hills, Custer Co., South Dakota; and the Brown Derby Mine, Ohio City, Gunnison Co., Colorado.

Common Mineral Associations

Quartz, Microcline, Tourmaline, Spodumene, Amblygonite

Distingushing Similar Minerals

Pink Muscovite - Very difficult to distinguish from Lepidolite.
Pink Chlorite - Not found in granite pegmatites.
Phlogopite - More reddish brown in color.

lepidolite Photos



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