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There are an alarming amount of tea first vendors that have very low cost "Yixing" teapots listed under the clay type Hei JinGang.

Of course never with the actual Chinese characters and searching it just pulls up listings from every tea shop you've ever heard of.

Namely Yunnan Sourcing and Verdant Tea as the big players but alibaba, aliexpress etc.

For those who don't know me I've done a pretty significant amount of research into clay types and (the wildly confusing) naming conventions. I have never encountered Hei JinGong as a clay subtype. There are a couple listings that have it vaguely described as ZiNi mixed with Bao Lan ZhuNi. Which doesn't even track since most of these listings are of black pots.

They are all low price (obviously I highly doubt of authentic Yixing clay) but I'm seeking to find out what they actually are made of. I've searched plausible combinations of Chinese characters most notably 黑金刚泥 (curse you homophones) and the closest I've come is a Baidu post saying :黑金刚是明代中国宜兴的一种窑变黑色紫砂器，取材于宜兴黄龙山的特殊泥料，在龙窑烧制过程中，高温烧出的珍惜紫砂品种。Calling it a black colored ming era "kiln-transformed" ware. Which does not explain the droves of brown ones listed. Searching this on Chinese marketplaces only gives black teapots however.

So what is this mysterious Hei JinGang clay?

servania wrote: ↑

Sun May 07, 2023 3:21 am

Of course never with the actual Chinese characters

Seems YS actually includes the characters in some listing, e.g. this one.

Hei Jin Gang Clay 黑金钢沙 is a blend of Zi Ni (Purple Clay) and Bao Lan Zhu Ni. It's dark in color with some purple and brown with a small amount of sand mixed in.

I'd put my money on there not being any strict definition of this category, i.e. a kind of "anything goes" (as long as it's blackish) mystery name that a certain type of vendor is more likely to use. No idea though.

Oh man.. that makes things even worse for vendor trustworthiness.

I found in my own research 黑金刚泥 as a newer clay type for black teapots likely a manganese oxide situation like HeiNi 黑泥

The link you provided has it as 黑金钢 however, which is a steel processing company and a manufacturer of various home improvement products like caulk and sealants. It is not a clay type what so ever. 钢 means steel.

It seems like Yunnan sourcing made a typo… at best. Even if they used the correct Gang (刚 instead of their typo 钢) then they are saying the pot is made of black Aquarium sand “黑金刚沙” as they used the beach sand 沙 not the rock ore sand 砂

Sad that this is the state of one of the biggest western facing tea companies.

servania wrote: ↑

Sun May 07, 2023 1:54 pm

The link you provided has it as 黑金钢 however, which is a steel processing company and a manufacturer of various home improvement products like caulk and sealants. It is not a clay type what so ever. 钢 means steel.

It seems like Yunnan sourcing made a typo… at best.

I think it's a typo (or YS just copied the characters he received from whatever company he's sourcing the pots from).

This article might be of interest.

Yeah so pretty much what I thought, two typos in one four character word is pretty bad.

黑金钢沙 what they originally wrote would be beach sand made by the HeiJin steel company.

黑金刚沙 would be a type of black aquarium sand

And 黑金刚砂 is what they were going for a dubious modern off shoot of 黑泥. Unknown clay and manganese oxide.

Thanks for the article link! Really tied up the loose ends on this.

servania wrote: ↑

Sun May 07, 2023 3:21 am

Which doesn't even track since most of these listings are of black pots.

I doubt that it is that, but black clay can also be achieved by reduction firing. As such, any Yixing clay can become black/various shades of grey.