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Related to vermiculite: Vermiculite Concrete
Any of a group of micaceous hydrated silicate minerals related to the chlorites and used in heat-expanded form as insulation and as a planting medium.
[Latin vermiculus, diminutive of vermis, worm; see vermicular + -ite.]
(Minerals) any of a group of micaceous minerals consisting mainly of hydrated silicate of magnesium, aluminium, and iron: on heating they expand and exfoliate and in this form are used in heat and sound insulation, fireproofing, and as a bedding medium for young plants
[C19: from vermicul(ar) + -ite1]
any of a group of platy minerals, hydrous silicates of aluminum, magnesium, and iron, that expand markedly on being heated: used for insulation and as a plant growth medium.