English China Research Articles

THE MICROSCOPIC EXAMINATION OF THE MINERAL CONSTITUENTS OF SOME AMERICAN CLAYS1

The difference in structure of the English and American clay grains and mineral constituents were examined under the microscope. English kaolin consists chiefly of crystalline Kaolin being similar to North Carolina kaolins in this respect. Georgia, South Carolina and some Pennsylvania clays consist largely of “colloidal” kaolin, which accounts for their difference in physical properties. The objectionable abrasive features of the American clays causing excessive wear to machinery can be readily overcome by more “refined” refining methods but it is impossible by any present known methods or process to transform the colloidal kaolinite particles of our transported clays into the crystalline plate-like structure of the English china clay. Our only hope therefore, of producing clays in this country which will be as satisfactory as those now imported, lies in the development of the crystalline kaolins. This is possible by better mining, blending and refining processes. However, the total tonnage of clay in our crystalline kaolin deposits is limited and if drawn upon intensively they would soon be exhausted. Minerals found present in the clays are chiefly muscovite, quartz, tourmaline, biotite, zircon, alkali feldspar, plagioclase, rutile, hydrated silica and hematite.

Political Prints Used on Old English China

Political Prints Used on Old English China