Any of a group of chemically and physically related aluminum silicate minerals, common in igneous and metamorphic rocks, characteristically splitting into flexible sheets used in insulation and electrical equipment.
Any of a group of lustrous rock-forming minerals consisting of hydrous silicates of aluminium, potassium, etc, in monoclinic crystalline form, occurring in igneous and metamorphic rock. Because of their resistance to electricity and heat they are used as dielectrics, in heating elements, etc
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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