və(r)ˈmikyəˌlīt, usu -īd.+V noun
( -s )
Etymology: Latin vermicul us + English -ite
: any of a number of micaceous minerals (as maconite) that are hydrous silicates derived generally from the alteration of mica which do not burn, are not harmed by water, and whose granules expand greatly at high temperatures to give a lightweight highly water-absorbent material that is used in seedbeds as a mulch, in plaster, mortar, and concrete as a substitute for sand, and as an insulating material in walls, floors, and ceilings