CLASSIFICATION AND NOMENCLATURE OF HYDROMICAS AND THEIR ROLE IN THE EARTH'S CRUST

The importance and abundance of hydromicas in the earth's crust has been underestimated. New calculations of data show up to 38 percent hydromicas in clay rocks. There is no longer doubt that hydromicas are the most important minerals in sediments and this group of minerals is among the first ten rock-forming minerals in the earth's crust. The presence of hydroxonium (H₃O) in hydromicas is no longer doubted but direct methods of determining amounts are not yet available. The present state of hydromica nomenclature is chaotic and over 50 names have been given to minerals in this group. Because of this, an orderly classification is necessary and such a system is presented in table form with an example of the determination of the proper position for one of the minerals of the hydromica group.