Encyclopedia Article


A type of igneous rock that can form intrusively, under the earth’s crust, or as part of an extrusive flow of lava. Once perlite cools it breaks into concentric pieces that look like rough, light-colored pearls, hence the name. Perlite can be used instead of sand in plaster and concrete. There are large deposits of perlite in the western United States.

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"Perlite" by Maja Dumat is licensed under CC BY.

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