vermiculite Meaning, Definition & Usage

  1. noun any of a group of yellow or brown hydrous silicate minerals having a micaceous structure

WordNet

Ver*mic"u*lite noun
Etymology
L. vermiculus, dim. of vermis worm.
Definitions
  1. (Min.) A group of minerals having, a micaceous structure. They are hydrous silicates, derived generally from the alteration of some kind of mica. So called because the scales, when heated, open out into wormlike forms.

Webster 1913