Kaolins, Kaolins, and Kaolins
Kaolin is an important industrial mineral and geological indicator. It occurs in hydrothermal, residual and sedimentary deposits. The first two are classed as primary occurrences and the third as secondary. The physical and chemical conditions under which kaolins form are at relatively low temperatures and pressures. The most common parent rocks are granites and rhyolites and the most common parent minerals are feldspars and muscovite. The kaolin minerals are kaolinite, halloysite, dickite and nacrite and by far the most common is kaolinite.
The physical and chemical properties of kaolin determine its ultimate utilization. Some kaolins can be used as paper coating clays, some as filler clays in several industries, some for ceramics and refractories and some for special uses. Important kaolin deposits that are briefly described are those in Australia, Brazil, China, Czechoslovakia, England, Germany, Indonesia, Japan, Mexico, New Zealand, Spain, Ukraine, and the United States.
The uses of kaolins are governed by several factors including the geological conditions under which the deposits formed, their mineralogical composition and physical, chemical and optical properties. The variable properties and uses and the differing occurrences and mineralogy explains why the title “Kaolins, Kaolins and Kaolins” was selected.