Crystalline Glazed Pottery
The crystal patterns form in much the same way frost gathers on a window, except that glaze, not water, is freezing, and the temperature inside the pottery kiln is about two thousand degrees Fahrenheit. Tiny amounts of metal added to the glaze cause spectacular variations in color.
The crystalline glazes are notoriously difficult to work with. The temperature of the kiln must be carefully controlled through several stages. The glaze will froth, spatter, and flow like water in the firing, and each piece must have a separate dish and pedestal perfectly fitted to protect it from the pool of molten glaze that gathers around the foot. Afterward, the artist must take a hammer and chisel to the delicate form and somehow break it free. The bottom of the pot is then ground and polished.
It is a nerve-wracking process and there are many losses. But the results are endlessly varied and surprising.