Abstract
Crystalline glaze structures resemble natural forms of minerals such as zincite, willemite, titanium, and various forms of silica. Many ceramic materials actively form crystals which vary widely, according to both the glaze composition and firing cycles. Crystals have varying sizes; from microcrystals similar to aventurines, to macro crystals which can be up to three inches in diameter. The current study aims at examining the different effects of coloring metal oxides introduced in the composition of macro crystalline glaze fired to 1250°C.

Several metal oxides are experimented with, including copper oxide, cobalt oxide, ferric oxide, lead oxide, and tin oxide. Under specific firing rates on 28 samples affecting the nucleation and growth of crystals applied over porcelain bodies, the results of yellowish, brownish and bluish glaze shades undergo a change of crystal formation and appearance leading to various aesthetic value.