Ceramics of indigenous peoples of the Americas
The clay body is a necessary component of pottery. Clay must be mined and purified in an often laborious process, and certain tribes have ceremonial protocols to gathering clay. Different tribes have different processes for processing clay, which can include drying in the sun, soaking in water for days, and repeatedly running through a screen or sieve. Acoma and other Pueblo pottery traditionally pound dry clay into a powder and then remove impurities by hand, then running the dry powder through a screen, mixing it with a dry temper, and then mixing water to create a plastic paste. In preparing the clay, potters spend hours wedging it to remove air pockets and humidity that could easily cause it to explode during firing. The clay then needs to "cure" over time.
Slate industry
The slate industry is the industry related to the extraction and processing of slate. Slate is either quarried from a "slate quarry" or reached by tunneling in a "slate mine". Common uses for slate include as a roofing material, a flooring material, gravestones and memorial tablets, and for electrical insulation. Slate mines are found around the world and the major slate mining region in the United Kingdom is Wales: in Cornwall there are a number of slate quarries (famously the village of Delabole) and in the Lake District there are numerous slate mines and quarries.