Disclosure: I have paid full price for Songyun's products from their amazon storefront. I had an opportunity to help translate some of their English product blurbs; I've not been compensated. I hope this company can provide go equipment to the world in a range of prices.

Songyun's wieqi stones are remarkably similar to the popular Yunzi: single or double convex in different colors and materials. They manufacture ceramic, melamine, and "jizi glaze" stones. It's the jizi that exhibit the signature Yunzi-like translucent green in the black stones.

They have a Chinese website that is presently being redesigned and they are adding new products. https://sywq.cn

Songyun also has a storefront on the amazon. Orders ship quickly from what must be stateside inventory but the current selection is quite limited. https://www.amazon.com/stores/SongYun/p ... f_=ast_bln

Hello!
I've found this shop on Taobao and I'm currently trying to figure out the match between the stones' material you mentioned and taobao's variant.

ceramic, melamine, and "jizi glaze"
雅瓷, 箕子, 精瓷
also 黑蓝款(新品上市) and 蓝墨款(新品上市)
https://tinyurl.com/mpzmra94

Easy: Don't order from taobao. Order directly from Songyun or amazon.

I've looked into sywq.cn, it, in particular, produces ceramic stones.
Could you clarify for not native speakers the difference between ceramic (pottery), porcelain, glass (not that glass, that is in your window at home? (marbles) ), concerning the stones' material?

As I noticed, the ceramic stones on sywq.cn are called "精瓷 fine porcelain" and "elegant porcelain" on Song Yun Taobao store. So, they must be synonyms.

In this forum one can come across "Japanese glass stones", korean Shin Kwang Baduk (新光, 신광바둑) Glass stones, 6 Brothers glass stones etc.

It would be easier for me to help you find the stones you want rather than try to translate Chinese, which I cannot do. You can contact the factory representatives using the email address for Songyun and google translate. Try to use simple and clear language that google can translate without idiom or error.

Songyun makes "jizi glaze weiqi stones"that are identical to the more familiar Yunzi stones; the black glow green when held up to light. Songyun also makes stones of ceramic, which are opaque, and melamine/plastic, which are useless. Songyun's stones are flat, single context, Chinese-style. However, they also make the Japanese-style double convex stones. The descriptions and illustrations are clear.

Glass stones vary widely in quality. The best I know of are Japanese; they are brilliant white and deep black, identical and regular in shape, and the glass is tough--won't shatter easily. Korean and Chinese glass stones tend to be cheaper glass, irregular, blobby, off-white, and streaked with visible flaws. Also, many of mine have chipped easily.

Here is my review of Songyun's colorful ceramic weiqi stones. The company makes eight different colors, I ordered four.

https://youtu.be/Y-Th0d7spew?si=xlXDbPtxvXBPLv-m