clǣg

Old English clǣg comes from Proto-Germanic *klajjaz, from a root meaning 'to stick' or 'to cling.' Clay is, etymologically, the sticky thing. This is accurate: clay minerals are tiny plate-shaped particles that hold water between their layers, creating the plasticity that makes clay moldable when wet and hard when fired. The same sticking property that named the material is the property that makes it useful. Every ceramic pot, brick, and tile in human history exploits the fact that clay clings to itself.

The oldest known ceramic figurine — the Venus of Dolní Věstonice, found in the Czech Republic — was made from fired clay approximately 29,000 years ago. The oldest known pottery vessels, found in Xianrendong Cave in China, date to approximately 18,000 BCE. Clay was the first synthetic material: humans took a natural substance, shaped it, and transformed it irreversibly through fire. The process cannot be undone. Fired clay cannot become unfired clay. The transformation is permanent — which is why archaeologists find pottery fragments at almost every human habitation site on earth.

In Mesopotamian, Egyptian, Greek, Chinese, and Abrahamic creation myths, humans are formed from clay or earth. The Hebrew name Adam may derive from adamah (earth, red clay). In the Quran, Allah creates humans from clay (ṭīn). In Greek mythology, Prometheus shapes humans from clay and water. The Yoruba deity Obatala molds humans from clay on the potter's wheel of creation. The metaphor is universal: we are shaped things. We came from the ground and will return to it.

Modern clay is an industrial commodity. Kaolin (china clay) is used in paper, paint, rubber, and pharmaceuticals. Bentonite is used in drilling mud for oil wells. Ball clay is used in ceramics. Fuller's earth (a type of clay) is used in cat litter. The sticky thing that was the first synthetic material is now an ingredient in products that have nothing to do with pottery.