Analysis of Yunzi stones (lead, etc)

[dracflamloc]

I had seen threads and conversations here and elsewhere about yunzi stones having lead and being composed of a formula known only by the creators, etc.

Well, a while back I ordered some double-convex yunzi stones from YMI. A couple of them came chipped or split in half so I sent them to a friend of mine who is a chemical engineer. He put them through one of these https://en.wikipedia.org/wiki/X-ray_fluorescence and gave me the results:

The stones are both primarily made of silicate. Likely tectosilicate or nesosilicate. There was a small iron peak and a small lead peak. The black stones had more carbon present, but otherwise were mostly identical. The iron is likely from whatever grinding/shaping process they went through.

https://en.wikipedia.org/wiki/Silicate_minerals

If you soak/wash them when you get them, the lead exposure should be extremely small. Basically, they are quite literally go "stones" (obviously manufactured)