Classification of Kaolins Exemplified by Their Textures in Scan Electron Micrographs

W. D. Keller
University of Missouri-Columbia, Columbia, Missouri 65201

Abstract: Varieties of kaolin, a rock, may be classified geologically, mineralogically, crystallographically, genetically, texturally, morphologically, by industrial use, and in other ways which are desired. In this paper, the first-order of classification used is geological, i.e., transported and residual, after which other categories are used as subdivisions.

Scan electron micrographs, SEM, of the textures of kaolin show that distinctive textures characterize the several categories of classification. Varieties in texture of kaolin include similarities to those typical of sedimentary, igneous and metamorphic rocks. Because word descriptions of the textures are inadequate in comparison to pictures of them, the reader is referred to the micrographs.

SEM's illustrate differences between kaolins which were transported, formed, or deposited from solution, a colloidal phase, or as orthodox clastic particles. The parent source of kaolin deposited, or “grown,” from solution may be difficult to ascertain. It is suggested that the total role of solution work in kaolin petrology can be more important than has ordinarily been credited.

Key Words: Deposition • Diagenesis • Kaolin • Texture • Transport

Clays and Clay Minerals; February 1978 v. 26; no. 1; p. 1-20; DOI: 10.1346/CCMN.1978.0260101
© 1978, The Clay Minerals Society
Clay Minerals Society (www.clays.org)