Home PageAbout MindatThe Mindat ManualHistory of MindatCopyright StatusWho We AreContact UsAdvertise on Mindat
Donate to MindatCorporate SponsorshipSponsor a PageSponsored PagesMindat AdvertisersAdvertise on Mindat
Learning CenterWhat is a mineral?The most common minerals on earthInformation for EducatorsMindat ArticlesThe ElementsThe Rock H. Currier Digital LibraryGeologic Time
Minerals by PropertiesMinerals by ChemistryAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
Mining CompaniesStatisticsUsersMineral MuseumsClubs & OrganizationsMineral Shows & EventsThe Mindat DirectoryDevice SettingsThe Mineral Quiz
Photo SearchPhoto GalleriesSearch by ColorNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day GalleryPhotography
Muscovite
A valid IMA mineral species - grandfathered
This page kindly sponsored in memory of Laszlo Z. Valachi
Colour:
White to colorless, silvery-white, and tinged various colors by impurities.
Lustre:
Vitreous, Silky, Pearly
Hardness:
2½
Specific Gravity:
2.77 - 2.88
Crystal System:
Monoclinic
Member of:
Name:
The earliest names attributable to muscovite include Muscovy Glass, Cat Silver, and Lapis Specularis (stone mirror); these names appearing in texts in the seventeenth century and before. The stand-alone name 'Muscovite' was used as early as 1794 by Johann Gottfried Schmeisser in his System of Mineralogy and is derived from the term "Muscovy glass," which was in common use by that time. Muscovy Province in Russia yielded sheet mica for a variety of uses. Muscovite and sometimes similar species were earlier called mica (Phillips and Kersey, 1706), glimmer (Phillips and Kersey, 1706), and isinglass (1747 according to OED) but all of these terms are still in use to some degree. It should be noted that mica, glimmer, and isinglass were also used for a variety of materials before these given dates and in those earlier times did not always indicate what would be a mineral, much less muscovite proper. Isinglass, for example, was originally used for a gelatinous bladder found in sturgeon.
Mica Group.
The most common of the Mica Group minerals, it is typically found as massively crystalline material in "books" or in flaky grains as a constituent of many rock types. It is clear with a pearly luster on cleavage faces, often having a sparkly look in rocks.
Several polytypes are known (see below); the most common one is the 2M1 polytype.
It can form a continuous series withceladonite andaluminoceladonite; intermediates are known as the varietyphengite and K-deficient variants asillite.
May be confused withmargarite and several lithium micas.
Visit gemdat.org forgemological information about Muscovite.
The most common of the Mica Group minerals, it is typically found as massively crystalline material in "books" or in flaky grains as a constituent of many rock types. It is clear with a pearly luster on cleavage faces, often having a sparkly look in rocks.
Several polytypes are known (see below); the most common one is the 2M1 polytype.
It can form a continuous series withceladonite andaluminoceladonite; intermediates are known as the varietyphengite and K-deficient variants asillite.
May be confused withmargarite and several lithium micas.
Visit gemdat.org forgemological information about Muscovite.
![KAl2(AlSi3O10)(OH)2](#"/photo-864771.html"><img src="/image.pl?url=https%3a%2f%2fwww.mindat.org%2fimagecache%2fed%2fd4%2f06894170017271925434909.jpg&f=jpg&w=240" alt="06894170017271925434909.jpg" /></a><div><b>Muscovite from Northern Karelia in the window of XVII century.</b><br /><br /><a href="/mt/?noimg=&dark=on&url=https%3a%2f%2fwww.mindat.org%2floc-189245.html">Northern Karelia, Republic of Karelia, Russia</a></div></div></div><div><div><span>Formula:</span><div class=){kind=link}