Jasper is a specific type of clay used in making this matte pottery. Barium sulfate is added to white clay. When the barium sulfate is mixed with the clay, it retains its pure white appearance. It is then colored usually in a light blue.
This distinctive black pottery is made from red iron clay with manganese dioxide added to it. The density of this clay when fired enables the potter to polish it a shiny black. The pearl white clay is made by adding cobalt oxide to kaolinic Cornish clay, which reacts somewhat like adding bleach to whiten clothes. Distinctive classical white cameos are applied to the pottery.
Round balls of jasper clay are placed on the potter's wheel and worked into the desired shape. The jasper clay has a distinctive feel and lots of elasticity, enabling the potter to shape it easily. Colors are mixed with the clay as it is being worked. This process is called wedging. The finished piece of pottery is fired in a kiln or pottery oven for 30 hours. The cameos are made in separate molds. The clay is pressed into the mold, removed and then dried. The cameos are then delicately attached to the finished clay pieces.