Any of a group of minerals characterized by highly perfect cleavage, the tendency of crystalline materials to split along definite crystallographic structural planes, which explains why it readily separates into very thin leaves. It is used in electric conductors, roof insulation, house paint, soil conditioner, cosmetics and toothpaste.
‘Wholly, holly, signal, signing,
Same, examining, but mining,
Scholar, vicar, and cigar,
Solar, mica, war and far.’
– Gerard Nolst Trenité, The Chaos