Traditional mining and mineralogy of geophagic clays from Limpopo and Free State provinces, South Africa
This paper is based on responses to questionnaires administered to 226 representative geophagic adults in Limpopo (Polokwane and Sekhukhune) and Free State (Qwaqwa and Mangaung) Provinces in South Africa, and semi-quantitative mineral identification of 40 geophagic clay samples from the same areas. Geophagic clays consumed were whitish, yellowish, khaki and black; mined from hills and mountains, river beds, valleys, excavation sites and termitaria. Geophagic individuals from Free State preferred whitish geophagic clays; and sometimes khaki. Yellowish clays were preferred mostly by geophagic individuals from Limpopo. The clays are mined using selective digging, hand grabbing and picking techniques. The clays are processed through sieving, slurrying, grinding and pounding. Baking, burning and boiling are some beneficiation techniques used to render the clays more palatable and to reduce their microbial load. Mineral phases identified in the clay samples were quartz, kaolinite, mica, feldspar, smectite, goethite, calcite, and dolomite. The properties of kaolinite and smectite were found to have a dominant influence on the nature of geophagic clays and hence on the health of those who consumed the clays. Further details regarding the potential of geophagic clays to provide medicinal benefits to the consumer were examined in this study. Geophagic practice is very deep rooted, globally distributed, and has spanned over several centuries. Renewed interest and study by the scientific research community has continued to generate new knowledge on this somewhat enigmatic practice. Further efforts to address and regulate geophagic clay consumption should be strongly advocated.
Key words: Colour, heat treatment, kaolinite, pounding, sieving.