The Clay Minerals Society Glossary for Clay Science Project

The Clay Minerals Society (CMS) Nomenclature Committee was asked by CMS Council to produce a glossary of clay science in 2003. The Committee developed several constraints on the development of the glossary: (1) it was decided to produce a glossary of clay terms, based on clay science. Terms may have other meanings in other disciplines, but the Committee did not want to include how other disciplines may use the terms (unless it is integral to the definition, e.g., as was the case of “particle size” for “clay”). The definitions provided below are terms as used in clay science and thus, this glossary is not a compendium, as is the case for the AGI Glossary. However, the definitions do not and should not stray from the basic science definitions as one would have in chemistry and physics. The point here was to include examples and perhaps direct the discussion toward clay science; the definition itself would conform to definitions in the other sciences. Unlike the AGI Glossary, where current usage is given even if that usage deviates from the original definition, the CMS Glossary provides the original definition and explains how the word may be currently and, perhaps incorrectly, used.