mica

Also known as mica minerals

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

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: White, colorless
Mineral.gravity: 2.8–3.0
Mineral.diagnostic: cleavage

via Wikipedia infobox

Wikidata facts

Mass: 797
Image: Biotite-Orthoclase-229808.jpg

Show 8 more facts

P13311: Hungary
Commons category: Mica
NIOSH Pocket Guide ID: 0431
immediately dangerous to life or health: 1500
vapor pressure: 0
time-weighted average exposure limit: 3
melting point: 700
IMA Mineral Symbol: Mca

Sources (5)

via Wikidata · CC0

~26 min read

Article

28 sections

Contents

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

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.