The ore material that stirs up the most debate among purple clay materials must be zhuni. The success rate for finished products of zhuni Teapots is relatively lower compared to other types of clay. There has always been a saying about zhuni that goes, “There's no zhuni without wrinkles,” and from some perspectives, this makes sense (though it only applies to some). Because the particle ratio content in zhuni is small and its drying and firing shrinkage rate is relatively high, it is prone to many unexpected defects, such as wrinkles, deformations, and cracks.

However, there are many zhuni teapots that do not have wrinkles. From historical works, we can see that those with wrinkles are only a part of them. The low success rate of zhuni teapots is due to multiple factors. The properties of ripe zhuni clay are very pronounced, and its permeability and evaporation performance of water are worse than other types of purple clay. When forming, one needs to carefully control the moisture level of the clay, the uniformity of the clay sheets, and the manufacturing method. Any misstep could easily reveal traces of the making process after firing.

Zhuni produced in places like Zhaozhuang has a higher shrinkage and deformation rate, so it is generally used for smaller products. The statement “There's no zhuni without wrinkles” is not entirely correct. For example, some Huanglong Mountain zhuni has properties between those of purple clay red mud and zhuni, with a larger particle ratio content, smaller drying and firing shrinkage, less prone to wrinkling, and capable of producing larger works. From some of the larger zhuni teapots left over from the Ming and Qing dynasties, we can find similar materials.

The difficulty in forming zhuni teapots lies in: the loose clay body, which makes it easy to crack during shaping; the difficulty in bonding; the large shrinkage ratio and low success rate; and the extreme difficulty in firing larger pieces. Some zhuni contains extremely high levels of iron, and if the firing temperature is slightly too high, iron will leach out, resulting in iron melting points. Therefore, regardless of who the master is, one cannot hold zhuni teapots to the same standards as teapots made from other types of clay. Generally, they all have certain flaws, either an ungraceful appearance or poor fit between the lid and the pot, or twisted spouts or handles, with defects being quite common.

If you come across a zhuni Teapot that is as neat as a teapot made from other types of clay, don't miss the opportunity, as owning one would be a matter of fate.

Image: ChaWo.com