I started learning about pottery after retiring from a career in technical instrumentation. My primary interest is raku pottery. Raku uses a special clay that can withstand large temperature shocks. The white hot pot is taken from the kiln and placed in a combustible such as paper. The burning paper pulls the oxygen out of the glaze to leave a colorful and interesting finish.
Most of my pots have a finish coating that protects them from air and UV light. Some are also coated with a water sealant, however raku is generally not safe for food storage or cooking.