A hydrous silicate of aluminium, iron, and magnesium, in foliated crystals, like mica, exfoliating in a remarkable manner when heated.

A kind of vermiculite found in North Carolina, of a pale greenish yellow colour with a tint of brown.

a mineral similar in composition to vermiculite but containing less water, and occurring as large yellow or brown scales.

A clay mineral now regarded as a variety of hydrobiotite.