Mica
Micas ( ) are a group of
silicate minerals whose outstanding physical characteristic is that individual mica
crystals can easily be split into extremely thin 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.
Micas are used in products such as
drywalls,
paints, fillers, especially in parts for automobiles, roofing and shingles, as well as in electronics. The mineral is used in cosmetics and food to add "shimmer" or "frost."
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