clay

Firing clay is the essential process of heating dried clay in a kiln to extremely high temperatures, permanently transforming it from soft, earthy material into hard, durable ceramic by removing water, burning off impurities, and fusing its mineral particles, making it strong, water-resistant, and ready for glazing or finishing. This typically happens in stages, like bisque firing (first, to remove moisture and harden it) and glaze firing (second, to melt glaze onto the piece).   

A kiln is a thermally insulated chamber, like a special, super-hot oven, used to harden, dry, or chemically transform materials through intense, controlled heat, primarily for making pottery, bricks, and ceramics, but also for drying wood or processing ores for cement. Kilns work by creating extremely high temperatures, often reaching over 2000°F (1090°C), to vitrify clay into durable ceramic or alter other substances, using fuels like electricity, gas, or wood.