Mineral resource of the Month: Mica

by U.S. Geological inspection Monday, November 3, 2014

Jason Christopher Willett, a mineral commodity specialist for the U.S. Geology Survey, compiled the following information top top mica.

You are watching: How are the minerals biotite mica and muscovite mica different


The mica mineral group contains 34 phyllosilicate minerals, all v a layered, platy texture. The mineral has been recognized for millennia: Mica was first mined in India around 4,000 year ago, whereby it to be used mainly in medicines. The Mayans used it because that decorative effect in stucco to make their temples sparkle in the sun. Today it is offered in every little thing from electrical products to makeup.

Mica is very reflective, and its wonderful cleavage enables it to separation into slim sheets; this tough, versatile sheets room the separating characteristic the the mineral group. Thin sheets room transparent or, if deep colored, translucent. Micas space stable as soon as exposed come electricity, light, moisture and extreme temperatures.

Commercial creates of mica can be grouped as either unmanufactured or manufactured. Unmanufactured mica have the right to be split into two classes: sheet mica and scrap mica, which contains flake mica. The bulk of manufactured mica, which has actually been shame or punched, is provided in electrical products.

The primary mica minerals offered in advertisement applications space biotite, muscovite and phlogopite. Biotite is typically used in its ground (particulate) type as a floor additive; muscovite and phlogopite have actually applications in sheet and ground forms. Muscovite paper mica is recovered just from pegmatite deposits; phlogopite paper mica is recovered from pyroxenites.

Muscovite is the major mica provided by the electrical industry come manufacture mica-based capacitors capable of operating at temperatures or frequencies that are devastating to polypropylene capacitors. Phlogopite mica is offered in plastic composites because that automotive applications since of the dimensional stability, increased stiffness and also improved warm distortion temperature.

Manufactured mica contains built-up mica, glass-bonded mica, ground mica, phosphate-bonded mica and reconstituted mica. Scrap mica is product that is below specifications for sheet mica since of substandard size, color or quality. Most scrap mica is provided as the raw product for two varieties of floor mica: wet-ground and also dry-ground.

Dry-ground mica is a finely divided material that is rough, through flakes showing significant surface damage and also no sheen. The is used in share compounds to bond, strengthen and also fill in the seams between drywall sheets; as an asbestos instead of in automotive products; in roofing shingle coatings to stop sticking; and in high-temperature and ultraviolet-radiation insulation.

Wet-ground mica is a finely divided product that has flakes with smooth rounded edges and also that retains its sheen. Wet-ground mica, which maintain the brilliance of its cleavage faces, is used generally in pearlescent paints by the automotive industry, but its reflective and also refractive properties make it critical ingredient in cosmetics as well, native eyeliner and eye zero to human body glitter, lipstick and nail polish.

For much more information top top mica and also other mineral resources, visit: minerals.usgs.gov/minerals.


In 2013, the United states produced about 48,000 metric loads of scrap and flake mica and around 79,000 metric loads of ground mica.

World annual production that mica is approximated to it is in 1.12 million metric tons.

Resources that scrap and also flake mica are obtainable in numerous countries, through the largest producers being China, Finland, India, Madagascar, southern Korea, Turkey, Russia and also the unified States.


“Mica” is originally a Latin word meaning “crumb.”

Mica was found in the U.S. At the Ruggles Mine in brand-new Hampshire in 1803; mining began soon after and also mica was exported come England to be supplied in family products.

White mica flakes are provided as snowflakes in Christmas decorations.

See more: How Much Was 1 Pound Worth In 1750 → 2021, $1,000 In 1750 → 2021

Mica sheets are provided for isinglass panels, i m sorry are used as viewing windows in coal, kerosene and also wood burn stoves.