Celadons

The Jade-Green Beauty of Goryeo Celadon 

Goryeo celadon has distinctive characteristics that set it apart from other types of pottery. Its clear, transparent glaze creates the jade-green color for which Goryeo celadon is famous. The glaze was made from materials containing quartz and feldspar, together with fluxes such as wood ash. Craftsmen ground these mineral materials into fine particles and mixed them with wood ash and water. The wood ash acted as a flux, allowing the glaze mixture to melt at a much lower temperature, around 1,200°C, rather than requiring temperatures approaching 1,700°C. This was important because the glaze had to melt at roughly the same temperature at which the pottery was fired. 

Iron in the glaze was also crucial to its color. During reduction firing, some Fe³⁺ was reduced to Fe²⁺. An appropriate balance between Fe²⁺ and Fe³⁺ helped produce the distinctive jade-green color of Goryeo celadon. The clear glaze also created a remarkable sense of depth. In grooves carved into the surface, more glaze accumulated, forming a thicker layer and producing a darker jade-green color than in the surrounding areas. These variations in color gave the surface a profound, three-dimensional quality. 

Goryeo celadon is also characterized by its elegant shapes and delicate forms. Firing such thin and carefully shaped vessels at high temperatures without deformation was itself a considerable technical challenge. Interestingly, however, the images decorating their surfaces were not always equally precise or delicate. They often depicted nature with simplified forms and rhythmic, sometimes even naive, lines.

The consumers of these precious objects, particularly the aristocrats of the 12th century, do not seem to have been bothered by such naive expressions. The elegant shape, jade-green color, and profound visual quality of Goryeo celadon may have mattered more than realistic representation. The designs did not need to reproduce nature precisely; they only needed to evoke it.