Different kinds of clay can have different properties, when fired. The most common types of finished wares are classified as earthenware, stoneware, and porcelain. ## Earthenware Earthenware has a slight porosity of about 3% to 7%. It will absorb water from its environment, and then gradually release it through evaporation. This makes it a good choice for garden pots (your typical red terra cotta pots found at your local hardware or gardening store). If glazed, earthenware may be sealed over, so that its surface is watertight. ## Stoneware Stoneware has a much lower porosity rating (1 to .5%), and can be glazed or unglazed. It is far more reliable for functional pottery. ## Porcelain Porcelain has zero porosity, and is likewise ideal for functional and decorative pottery. Porcelain is further characterized by its purity of color (white) and lack of mineral contaminants in the clay. This makes it an excellent surface for brightly colored decorations created with glaze, enamel or even paint.