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see micamica
, general term for a large group of minerals, hydrous silicates of aluminum and potassium, often containing magnesium, ferrous iron, ferric iron, sodium, and lithium and more rarely containing barium, chromium, and fluorine.
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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



(from Muscovy, the old name for Russia, from where large sheets of the mineral were exported to the West under the name of Muscovy glass), a mineral from the mica group with the empirical formula KA12[[AlSi3O10] • (OH)2. Crystals are tabular and in the monoclinic system. Basal cleavage is extremely perfect. Muscovite is easily split into very thin sheets. This is caused by its crystalline structure, which is composed of three-layer packets of two sheets of aluminum-oxygen and silicon-oxygen tetrahedrons connected through a layer of octahedrons, in the center of which are located aluminum ions, each surrounded by four oxygen ions and two OH groups. One-third of the octahedrons are not filled with aluminum ions. The packets are interconnected through potassium ions.

Muscovite has a hardness on Mohs’ scale of 2.5–3; its density is 2,760–3,100 kg/m3. The mineral is usually colorless; sometimes, light brown, pale green, or other colors. Its luster is vitreous; on the cleavage planes the luster is pearly or silvery. Muscovite is sometimes found as cryptocrystalline masses with a silky luster. In this form it is called sericite.

Muscovite is a widespread mineral and is found as a component of magmagene rocks and also metamorphic rocks such as granites, granite pegmatites, syenites, greisens, crystalline schists, and gneisses. Of industrial significance is the muscovite recovered from pegmatite veins, where the mineral occurs as large crystals or as accumulations measuring 1–2 m thick.

Muscovite is most frequently used in electrical insulation. In industry, it is used in the form of sheet mica (for insulators, condensers, and telephones), mica powder (for roofing paper, mica board, and fireproof paints), and mica products (for electrical insulating gaskets in electric instruments). In the USSR, muscovite deposits are found on the Kola Peninsula and in Eastern Siberia near Mama and Kanska. Muscovite is also found in India, the Malagasy Republic, Canada, the United States, and Brazil.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.


KAl2(AlSi3)O10(OH)2 One of the mica group of minerals, occurring in some granites and abundant in pegmatites; it is colorless, whitish, or pale brown, and the crystals are tabular sheets with prominent base and hexagonal or rhomboid outline; hardness is 2-2.5 on Mohs scale, and specific gravity is 2.7-3.1. Also known as common mica; mirror stone; moscovite; Muscovy glass; potash mica; white mica.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.


1. a native or inhabitant of Moscow
2. an archaic word for Russian
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
The Polish govemment was not ready to surrender Ukraine to Muscovite protection and was trying to secure young Khmel'nyts'kyi's loyalty by appealing to the terms of the Treaty of Hadiach (September 1658).
The most dramatic albite find was made inside the huge quartz pocket opened in June 2005: nearly 200 tons of albite were recovered, together with 300 tons of quartz and several dozen tons of associated muscovite and microcline.
Between the chapters on the renaissance and the baroque is an impressive section on the period Shvidkovsky identifies as 'Post-Byzantine "Mannerism" in the Muscovite State'.
A multi-disciplinary geochronological approach was used that involved U-Pb dating of tantalite, Re-Os dating ofmolybdenite, and [sup.40]Ar/[sup.39] Ar dating of muscovite. The results of these analyses are presented and discussed below.
The peraluminous character results in a high content of muscovite and a considerable presence of andalusite, sillimanite or cordierite.
The Muscovites bombarded the wooden walls with cannon, but to little effect, and infantry assaults were beaten off.
Typically yellow Muscovite render is used on the residential blocks, joining a diverse palette of materials used with great finesse.
Muscovite mica high purity wet-ground products with an ultra-high-aspect ratio offer reduced shrinkage and warpage, improved tensile and flexural strength, improved modulus, improved dielectric strength, cost-effectiveness, improved HDT, reduced permeability, microwave transparency, improved resistance to uv and retention properties when recycled.
The man responsible for the new Moscow is a short, stocky, 61-year-old carpenter's son and native Muscovite who, before turning to city government, made his career as a manager in the Soviet chemical industry.
This research examined sexual risk-taking behavior in Muscovite youth.
From 1850 to 1856 he was the editor of the Moscow journal Moskvityanin ("The Muscovite"), in which position he abandoned his earlier Romantic utopian fantasies and came to appreciate the native Russian virtues and the stability of existing institutions.