Natural clay from the earth and its minerals, imperative for survival of life on our planet, have been used for medicinal purposes for thousands of years. , and for some, the environmental and sustainability viewpoint that minerals will not harm the environment after disposal.
Clay minerals namely consist of silica, alumina, and/or magnesia, and sometimes varying degrees of iron, sodium, potassium, calcium, and water. Depending on the type of clay, as many as 75 trace minerals may be present.
Ochre
The first uses of ochre, or natural clay earth pigment, are thought to be by Homo erectus and Homo neanderthalensis who used ochre with water to soothe irritations, heal wounds, and clean skin. The theory is that they mimicked some animals who instinctively used clay/mud/minerals in this manner.
Jami Tarris/Stone/Getty Images
A traditional Himba woman covers her son with a fat and ochre mixture to protect him from sun, Kaokoland, Namibia.
The first recorded use of medicinal clay is on Mesopotamian clay tablets, dating to about 2500 B.C. The ancient Egyptian physicians used clays as anti-inflammatory agents and antiseptics. Clay was also used as a preservative during mummification.
Throughout history, clay has been used for dermatologic purposes. Aristotle (384-322 BC) made one of the first references to deliberately eating clay, earth, or soil by humans for therapeutic and religious purposes. Later, Marco Polo described in his travels seeing Muslim pilgrims cure fevers by ingesting “pink earth.”
The ochres have also long been found in indigenous and aboriginal art, and in current day Namibia, the Himba tribe have used Otjize paste (bright red clay consisting of butterfat, red ochre, and sometimes herbs) for their characteristic hairstyles and makeup, as well as for skin protection and as a soap replacement. Otjize is sacred to the culture and ethnic identity, signifying the beauty of their hair and skin and a sense of oneness with their surroundings (the earth). There are also many instances of religious, folklore, or mythological references of creation of life or creation of humankind from clay.
Dermatologic uses
The most common uses of clay in dermatology are for treatment of acne and in spa or cosmeceutical preparations to purportedly draw out dirt, impurities, or toxins.
Dr. Naissan O. Wesley
Clay minerals are most commonly formed from prolonged chemical weathering of silicate-bearing rocks. Clay can also be formed from hydrothermal or volcanic activity. Chemical weathering takes place mainly by acid hydrolysis resulting from low concentrations of carbonic acid, dissolved in rainwater or released by plant roots. Clays differ in composition and structure depending upon the source. Simplistically, clay is structured in two layers, organized in various shapes, with varying minerals and electrical charges. The electric charge of clay allows the adsorption of various minerals, water, heavy and radioactive metals, free radicals, and other potentially unwanted byproducts of metabolic activity. With antibacterial properties and adsorptive properties, clay is often used to dry out acne or oily skin and/or to improve the appearance of large pores.