HISTORICAL DEVELOPMENT IN THE CLASSIFICATION OF KAOLIN SUBGROUP

Kaolin is a subgroup of clay minerals having polytypes namely kaolinite, dickite, and nacrite and a polymorph called halloysite. Kaolinite is of special interest and it constitutes clays like ball-clay, chinaclay, fire-clay, flint-clay etc. It has diverse industrial applications including ceramics, paper, rubber and pharmaceuticals. In addition, it has been of interest to academics and researchers in the disciplines of geology, agriculture, mineralogy, engineering, dentistry, crystallography and microscopy. Because each of the above academic disciplines has looked at kaolinite from their own angles and interest, a great confusion has resulted with respect to its name and classification. Thus different organizations arranged conferences, seminars, workshops and lectures to reach a universally accepted classification and names regarding clays and clay minerals. This study reviews the efforts, agreements and recommendations that have been made by international experts in achieving this goal.