The role of swelling clay in kimberlite weathering

Weathering tests on kimberlites from several sources indicate that the single most important aspect when considering kimberlite weathering is the presence of swelling clay. Certain kimberlites, containing no swelling clay, are non-weatherable even under considerably aggravated conditions. For other kimberlites, increasing swelling clay content correlates with more severe weathering. The cation exchange capacity (CEC) is a useful parameter that correlates with the swelling clay content; the CEC can be determined relatively fast and economically compared with determination of the swelling clay content by X-ray diffraction.