Chinese Yixing Purple Clay zisha Teapot for black tea and green tea

1. Description

Zisha is a mixture of kaolin, quartz and mica, with a high content of iron oxide. It is mined principally at Huanglongshan and Zhaozhuangshan and has a somewhat sandy texture. The process of preparing the clay is lengthy and was traditionally regarded as a trade secret. Typical firing temperature is between 1100C – 1200C in an oxidizing atmosphere.

The raw materials for yixing clay are buried deep underground, sometimes under heavy sedimentary rock formations. When excavated, it is usually located within stratified layers of other clays. The seam of yixing zisha can be as thick as a several decimeters, up to a meter. Yixing clays consist of fine iron-containing silt, with mica, kaolinite and varying quantities of quartz and iron ores as its main mineral constituents.

Processing of raw zisha yixing clay involves removing the clay from the underlying strata, drying it under the sun in open stalls, and then pulverizing the dried clay pieces into fine particles. The clay powder then undergoes air screening to isolate clay particles of the finest grit size. The screened clay is then mixed with water in a cement mixer to a thick paste, piled into heaps, and vacuum processed to remove air bubbles, in addition to some moisture from the clay mixture. The quality and quantity of water in yixing clay is critical in that it determines the quality of the stoneware products produced. After this processing, the resulting clay is then ready to be used.

The appearance of yixing products, such as its colour or texture, can be enriched and altered through the addition of various metal oxides into the yixing clay, through the manipulation of firing temperatures, and also from regulating the kiln atmosphere (oxidative versus reductive).

2. Details

Yixing clay (Zisha) is famous because the good quality soil from that region creates clay that producesnice and collectible art pieces teapot or pot. Besides the material, the value also comes from the shapeand the art work on the surface, the calligraphy or the graphic sometimes from skillful artists.