A New Collection of Crystalline Pottery
How are crystals grown?
The crystalline process is much like a chemistry lab project. Exact control of the kiln temperatures encourages the zinc oxide in the glaze to restructure itself into a crystal pattern. Crystalline glazes are best fired in electric kilns rather than gas because the electric kilns have the atmosphere that encourages crystal formation and are more easily controlled. If the temperature is too high, the crystal melts away, and if the perfect temperature is not reached, it causes the formation to freeze and stop growing.
The cooling period at 2000 degrees is extended over several hours to encourage the crystal nucleus to gather more zinc and grow larger. A seven hour period can grow a crystal to 3 inches.
In the Ming Dynasty, the Chinese pottery would sometimes form crystals during the cooling period of the wood fired kilns. These were considered minor flaws. The French discovered the technique of forming crystals during the Art Nouveau era, with the desire to reproduce antique Chinese porcelains.
Today's artists work with specialty porcelain clays that they formulate themselves, and work years at developing unique glazes. Various metal oxides are mixed with the glazes to create specific colors like cobalt blue and copper greens.
Of all pottery making techniques, crystalline glazes are one of the most difficult. The pottery that survives the process is highly prized and guaranteed to be a one-of-a-kind. |
