Letsoku

Letsoku is a clay-like soil used by several peoples of Southern Africa and other parts of the continent. The Sotho-Tswana describe a number of clay soils as letsoku; other peoples name it differently, such as chomane in Shona, ilibovu in Swati, imbola in Xhosa and luvhundi in Venda. It is a native earth coloured with hydrated iron oxide, ranging from pale yellow to deep red, brown, off-white, grey and black. It comes in a clayey kind and a chalky kind. The raw chunks are crushed with a pestle and mortar or ground on a stone, then sieved to a fine powder. Wikipedia says it is used in cosmetics, to mark stages of life such as initiation schools and marriage, in medicine, to protect crops and for protection against lightning and witchcraft.