For functional ware I use stoneware with fine or coarse grog for my. Stoneware belongs together with porcelain to sintered ceramic. The water absorption rate is after the glaze firing about 3%; therefore it is frost resistant and suitable also for garden ceramic. Stoneware consists of caolinite, illite, silicon and feldspar often mixed with grog (fired, grounded clay). For decoration I use lead free feldspar brushed or dipped glazes. Bisque is fired at 960°C/1700F, glaze firing at 1250°C/2480F, so that firm sintered ceramic originates.