mica
Sign in to savethumb|Sheets of mica thumb|Optical mineralogy|Photomicrographs of a thin section containing phlogopite. In cross-polarized light on the left, plane-polarized light on the right. thumb|Dark mica from eastern Ontario
AI overview
Mica is a naturally occurring mineral that forms in thin, transparent sheets that can be easily separated from each other. It is valued for its optical properties and heat resistance, making it useful in various industrial and scientific applications.
AI-generated from the Wikipedia summary — may contain errors.
Key facts
- Mineral.name
- Mica
- Mineral.image
- Mica (6911818878).jpg
- Mineral.imagesize
- 260px
- Mineral.category
- Phyllosilicate minerals
- Mineral.formula
- AB2–3(X, Si)4O10(O, F, OH)2
- Mineral.IMAsymbol
- Mca
- Mineral.color
- purple, rosy, silver, gray (lepidolite); dark green, brown, black (biotite); yellowish-brown, green-white (phlogopite); colorless, transparent (muscovite)
- Mineral.cleavage
- Nearly perfect
- Mineral.fracture
- flaky
- Mineral.mohs
- 2.5–4 (lepidolite); 2.5–3 (biotite); 2.5–3 (phlogopite); 2–2.5 (muscovite)
- Mineral.luster
- pearly, vitreous
- Mineral.streak
Article
28 sectionsContents
- Properties and structure
- Classification
- Dioctahedral micas
- Trioctahedral micas
- Interlayer-deficient micas
- Occurrence and production
- Uses
- Useful properties
- Ground mica
- Paints and cosmetics
- Built-up mica
- Sheet mica
- Electrical and electronic
- Atomic force microscopy
- Peepholes
- Etymology
- Early history
- Mica powder
- Medicine
- Health impact
- United States
- Ireland
- Substitutes
- In popular culture
- See also
- References
- Sources
- External links
thumb|Sheets of mica thumb|Optical mineralogy|Photomicrographs of a thin section containing phlogopite. In cross-polarized light on the left, plane-polarized light on the right. thumb|Dark mica from eastern Ontario
Micas ( ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into fragile elastic plates. This characteristic is described as perfect basal cleavage. Mica is common in igneous and metamorphic rock and is occasionally found as small flakes in sedimentary rock. It is particularly prominent in many granites, pegmatites, and schists, and "books" (large individual crystals) of mica several feet across have been found in some pegmatites.