On 2015-02-20 01:22:21 +0000, Scott Dorsey said:

> So, my parents gave us a set of yixing teaware for Christmas, labelled
> "Tang Chaoxing Purple Teapots." They smelled right, the color seemed
> right, but I really don't have any idea how to tell if this stuff is real
> or not.
>
> So... I took it into work and asked the mass spectro guys to put it in
> the machine. They did, and they got this out:
>
> Element % +/-
> ------- ----- ----
> Si 46.08 0.19
> Fe 28.31 0.19
> Al 21.72 0.20
> Ti 2.05 0.14
> Mn 2.22 0.06
> V 0.22 0.06
> P 0.20 0.01
> Zr 0.16 0.00
> Pb 0.02 0.01
>
> This resulted in all of the nondestructive testing people hanging out and
> asking "what the hell IS this?" I'm guessing it is real yixing from the
> high iron content, although now I am really curious what form of iron salt
> is actually in there. The detectable lead content is probably worrisome
> to somebody. But what is with the titanium? Does it just come along for
> free with the alumina?
>
> Anyway, I found this interesting and if this helps anyone else identify
> yixing ware, feel free to use it. The stuff definitely does have some
> magnetic properties; it will change inductance of a coil if it's in the
> middle, like a ferrite. The ND guys kept asking if it was actually a
> ferrite. I'm not sure what to say...
> --scott

The "real" red yixing ran out in the 1970s or so. There are several
substitutes on the market varying in color from red (not the same lode
of clay as the original) to purple to brown. In the past it seems that
yixing clay of varying shades was used as well.

Since manufacturers of these products do not seem interested in details
about the production of their wares, it's tough to say for certain that
we know much of anything about them. The high aluminum content in your
sample is suspicious to me though - seems way too high. The Chinese
are sneaky and have been known to put all kinds of fillers into things
if they can get away with it.

If you can acquire a few samples of the older ware, preferably
pre-industrial, and have the mass spectro guys run those too I think it
would be most helpful.

Thanks for the post.