Jasperware
The formula for Jasper, a dense white stoneware, was Josiah Wedgwood’s most closely guarded secret. For the chemically-inclined, we know that it contains one part calcined flint, three parts purbeck clay, one quarter part fired and washed alabaster, and six parts sulfate of barium, all fired at about 1200-1250 degrees centigrade. When thinly potted and fired at slightly higher temperatures, Jasper becomes translucent and rings like porcelain.
“Invented” by Wedgwood after many [...] Click here to continue reading.