Exfoliation of Vermiculite by Chemical Means

SPECIMENS of vermiculite from different localities have been examined in the laboratories of the Mineral Resources Department of the Imperial Institute in the course of an investigation into possible Empire sources of supply, and an interesting phenomenon has been observed in connexion with the expansion of the mineral, a property on which its commercial value depends. This expansion is usually brought about by heating the material, and a record of an instance in which it has been effected by chemical treatment appears to be of scientific interest.