About the clay in Yixing today

[Chi-Lin Lu]

Hi, friends, I am Chi-Lin Lu, the administrator of the group of early tea pot ( https://www.facebook.com/groups/teapot2/) . I just joint this forum and happy to be member of it. I have read some articles discuss about the clay of pot, so I like to share one of my article in 2016 after I visited Yixing, China to everyone. Just hope it is helpful to understand Yixing clay, if I have time, I would like to share more information about clay and pot with everyone.
關於宜興的「紫砂礦料」現況
About the clay in Yixing today
許多玩家都知道早期壺貴在「土胎」，因為早期土胎已不可復得。
Most of the teapot collectors knew the "clay" is the most precious part of early-period teapot, because old clay is unreachable today.
之前有不甚了解早期壺的朋友在爭辯説「宜興現在還是買得到土啊」，而推論早期土胎並沒有什麼特別珍貴之處。
Some friends argued that there are still selling clay in Yixing now, so the early-period clay is not as precious as we thought.
昨天早上特別抽空跑了一趟黃龍山與青龍山，利用這次機會簡單的跟大家說明個人看到的情況。
Yesterday, we went to Huang Long Shan and Qing Long Shan. By this opportunity I like to explain some of the situation which I saw over there to everyone.
大家都知道當年一廠的土主要是來自黃龍山（見註一），我特地請大陸朋友找來一位當地(丁蜀鎭）出生長大的小哥擔任我們的司機兼導遊去親探了黃龍山與青龍山。
We knew the Huang Long Shan was the major clay source of F1 (see footnote 1). We found a local guide who was born and grew up at local town (Ding Shu Zhen) took us to visit Huang Long Shan and Qing Long Shan.
事實是當年的原址，不只早已停產，政府為了保存僅有礦脈，已延著山邊築起長牆，一般人不要説採，連看都看不到。
The fact I saw is the former mine site was not only closed but the government also builded a long wall to protect it. People almost can not see it, not to mention to reach it.
當地出生的小哥還帶著我們由山後的古村莊繞上去看，整個黃龍山一廠當年採礦舊址已完全被封了。
The local guide took us to detour the wall from an old small village in the other side of mountain. The whole former mine sites of F1 was all sealed.
我們在丁蜀鎮街上確實看到不少賣「土胎」的商家，但這些土胎和一廠60及70年代所挖的礦料大多是不同的，主要是由附近或其他礦坑所產。
We indeed found a lot of stores are selling "clay" in Ding Shu Zhen. But these clay were different with the 1960s and 1970s. Most were extract at the nearby mines around Yixing.
另外許多大名家的家中都存有老土礦是事實，也尚有專業土胎商家出售號稱以前存下的舊土(4號坑)，但近代所開採的土與60及70年代的土質還是有所不同的。
Besides, a lot of teapot makers they had stored many old clay is true, and there are also many vendors selling the "old clay" which was claimed was extracted before the mines were closed (I think most of it were after 80s).
這次拍賣會我們也上手了許多年輕一輩陶手的精品，作工不在話下，但土胎多是新礦為主，明顯可看出差別。
In 2016 auction, we saw a lot of new generation of pot artists, their works are delicate, but the clay and kiln is totally different with old one.
結論：1、宜興確實現在還買得到紫砂土，但與60及70年代開採的一廠礦料並不全然相同。2、請大家珍惜手上的早期壺，因為那土胎真的很少很少了。您打破一把，全世界就少一把。
Conclusion: 1.We still can buy clay in Yixing now, but it's different mines with 60s and 70s' F1. 2.Please cherish the early-period teapots, that clay is really difficult to find now. If we broken one, the total number of early-period teapot in the world will minus one.
《以上個人心得，供大家參考》
"This is my personal understand, just for your reference. "
註一：根據我們實地拜訪當年的老技工表示，當年一廠的用土主要是來自黃龍山，但不以黃龍山為限，而是取當年整個宜興地區可以取得的最佳的土胎來作壺。
Footnote 1: According the memory of old pot makers, most of the clay used by F1 was from Haung Long Shan, but not limited on it. They used the best clay at that time to make teapots.

[Chi-Lin Lu]

The major problem of some clay today, is the adding of oxide. Actually before 80s, only few special color had add oxide, but after mid-80s oxide was more commonly added in Yixing. Adding oxide doesn't mean the pot is toxic, it depends on what kind of oxide and the temperature of firing. But in recent years, the price of Yixing clay is higher and higher. I knew some bad clay venders add some toxic oxide into non-Yixing clay to cheat customers. Even the Chinese CCTV had made a program reported it few yeas ago. So when we buy pots, we have to take care about this issue. Strange color or smell should be avoided.

[steanze]

Dear Dr. Lv, thanks for the informative post! It's an honor for us to have you on this forum

[Chi-Lin Lu]

Dear Dr. Lv, thanks for the informative post! It's an honor for us to have you on this forum

Hi, Steanze, thank you.

[Victoria]

Dear Dr. Lv, thanks for the informative post! It's an honor for us to have you on this forum

Hi, Steanze, thank you.

Yes it is very special to have you join us here at TeaForum. Many Yixing collectors here. Welcome.

[Atlas]

Hi Dr Lu, thanks for joining and sharing your experience.

I was wondering, to the best of your knowledge, do all pots using toxic oxides have a strange/different smell to them, or is this just one indication of a bad pot?

Do you know which particular oxides of concern are used? Knowing that could provide information about which colours should be treated with the most suspicion (perhaps).

[Shane]

If there is no smell, should there still be a concern?

[Bok]

Thank you for sharing your knowledge and welcome to the forum!

[Chi-Lin Lu]

Hi,

Not all pots use toxic oxides have a strange smell, it's just one of the indication. The color and appearance of pot are the other indications. Of course if we want to 100% sure, the scientific test is best.
The following link is the program of Chinese CCTV, it's in Chinese, but in the film we can see the workers add different kinds of oxide into the clay. The clay producer admit they add many different kinds of oxide into it. Including manganese, cobalt, cadmium, nickel, barium carbonate...etc.


In the second film, they tested 15 samples of the metal-ion dissolved in the water of pots, found 13 samples have high metal-ion dissolved in the water.
About the most suspicion colors including blue, green, dark yellow, dark black and shiny red. Basically, we should avoid those colors look unnatural and artificial.

However, I have to emphasize this is the problem for poor quality pots, not every pot in Yixing has this problem. We still can find a lot of good pots in Yixing.

Hi Dr Lu, thanks for joining and sharing your experience.

I was wondering, to the best of your knowledge, do all pots using toxic oxides have a strange/different smell to them, or is this just one indication of a bad pot?

Do you know which particular oxides of concern are used? Knowing that could provide information about which colours should be treated with the most suspicion (perhaps).

[Chi-Lin Lu]

Thank you for sharing your knowledge and welcome to the forum!

Thank you.

[Atlas]

Thanks Dr Lu!

I imagine it wouldn't be worth it for cheap pots, but at $11 it seems that something like THIS might be a good idea if someone has any concerns.

[tealifehk]

Welcome Dr Lu, and thank you for sharing your experience! I smell a very strange odor from some modern purple clay pots that are sold with signed certificates and all. I don't buy any odd colored clays but even the purple clay appears to be an issue in many cases now.

[Chi-Lin Lu]

Welcome Dr Lu, and thank you for sharing your experience! I smell a very strange odor from some modern purple clay pots that are sold with signed certificates and all. I don't buy any odd colored clays but even the purple clay appears to be an issue in many cases now.

Thank you.
Most of the modern pot artists bought their clay from the clay market. It's different with old time, they have to learn from refining clay as a beginner. Some artists may care about this oxides issue, but some may not.
I agree some modern purple clays had add oxides, most of this kind of clay has homogeneous granules and unnatural color, compare with nature one.
Any pots with strange odor should be avoided, even it is safe, it's bad for tea fragrance.

[tealifehk]

Welcome Dr Lu, and thank you for sharing your experience! I smell a very strange odor from some modern purple clay pots that are sold with signed certificates and all. I don't buy any odd colored clays but even the purple clay appears to be an issue in many cases now.

Thank you.
Most of the modern pot artists bought their clay from the clay market. It's different with old time, they have to learn from refining clay as a beginner. Some artists may care about this oxides issue, but some may not.
I agree some modern purple clays had add oxides, most of this kind of clay has homogeneous granules and unnatural color, compare with nature one.
Any pots with strange odor should be avoided, even it is safe, it's bad for tea fragrance.

The odor doesn't carry over into the tea liquor but I have serious concerns about the safety of this clay and refuse to use it now! I definitely agree that any pot with a strange odor should not be used!

[Chi-Lin Lu]

Thanks Dr Lu!

I imagine it wouldn't be worth it for cheap pots, but at $11 it seems that something like THIS might be a good idea if someone has any concerns.

Wow, this looks good. How about the sensitivity of it ? Because the metal-ion dissolved should be very little, if the sensitivity is not high enough, may not be examined.