• Registered: 2008-11-05
  • Posts: 111

Topic: What to look for in clay

1. extra dots

Yixing clay is of minerals such as iron, silicate, manganese etc..and it differs depending on where

silver (mica), white (silica), black (mangaese or iron)

silver dots are often found on Mt. Huanglong clay, from deep inside, almost never found on Zhuni. It's one way I discern Huanglongshan Hongni from Chuanbu or Zhaozhuang Hongni and Di Cao Qing from Zini. Old factory-1 Hongni had many silver dots :)

white dots are helpful to discern whether it contains chemical oxide or not, for example, CR (cultural revolution) clays are known for white dots then after late 70's (started using oxide powder) they are gone but sometimes not, on early-Qingshuini. It could be used for Zhuni as well.

black dots can be used helpfully as well, and it has many types about it. If it's one sole big dots, it could be sign of being fired at wood-kiln or made during early-day (before 80's). If it's numerous dots, it could be manganese. If it's on red clay, then I think could be of iron.

2. dry or glossy

It is as well very important factor to discern. Red clay, Xiao Mei Yao Zhuni, Hu Fu Zhuni, Nenni have drier surface than Huanglong/Zhaozhuang Zhuni and Mt. Huanglong old Hongni has dry surface than other Hongni. Di Cao Qing is known for oily skin too. Kiln also affects it. Gas kiln and late factory-1's famous tunnel kiln have known for firing pots oily :)

3. weight

I personally like heavy clays (Tie Sha ni, Zhuni, Di Cao Qing, etc). They didn't disappont me. Many times heaviness comes from density and amount of iron. Zhaozhuang Zhuni a bit heavier than other Zhuni, also Di Cao Qing and other clay from deep inside shows this character.

4. color (water color-水色)

Definately important factor. The Chinese call it water-color, it's a color tone that turns brighter to sunshine or light. No other Zhuni has brighter and stronger orange tone than Zhaozhuang golden Zhuni (aka Zhu-Hongni). Some low-quality Ben Shan Luni, Mt. Huanglong Lao Hongni, Xiao Hongni Nenni don't have this character. Kiln also affects it, old-time wood-kiln was known for firing pots darker, historically, best kiln for color is known as factory-1 tunnel kiln (used during 70's to 90's)

5.softness

Good clay all is soft :P


these are factors ppl use to check up but not all-the-way right :) but I think it could be more helpful than sand-clay 泥沙 way, latter is what potters and clay-makers use often

一杯一杯復一杯
  • Registered: 2010-04-21
  • Posts: 6

Re: What to look for in clay

Once again, thanks for this very helpful post Charles! I partially understand why many good clay pots will appear glossy/oily. I sometimes describe certain clays (often good Hong Ni) as having the appearance of satin. Where I get confused is trying to tell the difference between gloss form a) the natural clay b) burnishing or polishing done by the potter, and c) gloss caused by lots of use and tea oils. Perhaps you could talk more about these points, or even post some photos to show the difference?

Thanks again for your help. I am actually red/green colorblind, so trying to evaluate a pot based on its color is very difficult for me. I have to pay closer attention to all these other important characteristics.

  • Registered: 2008-11-05
  • Posts: 111

Re: What to look for in clay

tingjunkie wrote:

Once again, thanks for this very helpful post Charles! I partially understand why many good clay pots will appear glossy/oily. I sometimes describe certain clays (often good Hong Ni) as having the appearance of satin. Where I get confused is trying to tell the difference between gloss form a) the natural clay b) burnishing or polishing done by the potter, and c) gloss caused by lots of use and tea oils. Perhaps you could talk more about these points, or even post some photos to show the difference?

Thanks again for your help. I am actually red/green colorblind, so trying to evaluate a pot based on its color is very difficult for me. I have to pay closer attention to all these other important characteristics.

Not sure glossy/oily has to do with quality of clay, I understand good clay as rather quickly seasoned. Silky Hongni I met was 2 kinds, Mt. Huanglong Lao Hongni (dry texture) and Chuanbu Hongni. Both were used by factory-1. Chuanbu Hongni is most common factory-1 Hongni and brightest color tone among all Hongni, shrinks high, first sight looks like Zhuni but it's light.

clay polished by potter or used ones, you can know by seeing inside the lid, if done, only outsurface will look glossy while lid inside is not. not sure if my answer is enough actually I didn't quite get your question :P

I don't follow "this and that" theory, it's like comparing natural vitamins and vitamin suppliments :)

一杯一杯復一杯