Porcelain is made from clay — but not just any type of clay. The clay used to create porcelain is often called China clay, and it contains a high percentage of a mineral known as kaolinite along with silica, feldspar and other mineral oxides which together are responsible for the strength and durability of porcelain.
This combo is put into a kiln and fired at extremely high temperatures (approximately 2550℉ / 1400℃). The result is a super dense material that is nearly completely impervious to stains, heat, UV rays, scratching, chips, and cracks.