[ və'mɪkjʊlʌɪt ]
■ noun a yellow or brown mineral found as an alteration product of mica and other minerals, used for thermal insulation or as a moisture-retentive medium for growing plants.
Origin
C19: from L. vermiculari 'be full of worms' (because on expansion due to heat, it shoots out forms resembling small worms) + -ite 1 .