tingjunkie wrote:Due to language differences, and old traditional terms, locking down exact names for Yixing clays is nearly impossible. Add to that that many clays are blends, and an infinity of naming possibilities exist. Personally I feel calling all Yixing clay "zisha" is archaic and pretty daft. Zisha translates to purple sand, so why would red, yellow, black or green clays be included? Makes no sense.
I think you're interpreting 'zisha' a little too literally, maybe. Also, I think the term refers to pre-firing color, which is often quite different from the color of the fired piece.
In general, you will often hear people use 'zisha hu' as an umbrella term, and many teapot books and companies have 'zisha' in their name, so I think it's a bit of a stretch to say it's either 'archaic' or 'daft'.
From one of my teapot books (in the English version of the article). Note the use of 'zisha' as both a general term and a more specific type:
The raw materials of zisha teapots are generally called zisha clay, and in fact, there are three basic clays for making zisha teapots: purple clay (zisha), light-brown clay (benshanlu), and red clay (zhusha), and they are different in quality and color in differnt[sic] digging areas. When the wares are fired, they will represent in different colors. This is why zisha clay also enjoys the reputation of "multicolored clay". After firing, teapots will take on a different color. Teapots of purple clay will show themselves in various shades of purplish brown; most of our exhibits are of this category. The ones of benshanlu will be in buff [....] The ones of red clay, also called zhuni teapots, will become vermeil[sic] [....]
All these three kinds of clays exist in jianni (a kind of hard rock) and nenni (a kind of soft mud). They were found in mined kaolin, so they are also called "top clay", and only around of Yixing clay is zisha clay. Teapots can be made of a single clay, or a mixture of several clays; for example, the duan clayed Pan teapot (cat. no. 866) is made of an intermmixture of two clays.
In addition, there was documented a clay called tuanshan clay (3), a type of purple clay, in bronze color after being fired, but had been exhausted by the late period of Qing dynasty. Then due to the elegant color and luster of this fine clay, the potters substituted an intermixture of purple clay and benshanlu for tuanshan clay, which is called duan clay, a man-made clay of top quality.
[From Appreciation of Zisha Teapots
《砂壶匯赏》ISBN 9628477782, p22]
And, from another book:
Compared with the potting clay other regions produce, purple clay [n.b. - 'zishani' is the term used in the Chinese version] possesses an unusually high iron content, usually in the 8-10% range, but reaching as much as 11-12% at times. Consequently, the color it reveals after firing can range from a reddish-brown to its eponymous purple, including hues that have been variously described as "dark kidney," "winter pear,"light ocre," and simply "iron." In fact, that which is generally referred to as "purple-earth clay" can actually be broken down into three categories, based on color and potting characteristics, termed purple, red, and green clays [n.b. - 'ni' is used here]. Of these, the purple clay group itself contains many varying sub-groups, which together constitute the principle[sic] pool of ingredients to purple-earthenware production.
[From 古壶之美 (Guhu Zhimei) "Chinese Yixing Teawares from the Collection of the Mai Foundation", ISBN 9579748292, p56]