http://houdeblog.com/?p=130
And an e-mail I received in the past from a Yixing-based vendor in regards to zhuni:
"Zhu Ni is typically found at the bottom of the mines and it is hard as
a rock it is also called "Shi huang ni" roughly translated into "Bone of
Rock"
Rare, yes it is semi-rare it is harder and harder to find. Most of
the clay has been mined and it has been kept in storage for years and
been sold off bit by bit to artists at high and higher prices. Most
of the clay is in private stock today with less and less being mined
every year. Just like any clay no matter what the color, they all
have different grades. So not all clay even Zhu Ni is top grade.
Color depends on Iron Content of the clay. Wrinkly, Orange Peel and
pear skin texture are not specific to Zhu Ni. An artist can mix the
clay with larger gains of Zi Sha clay to give it a texture. In
addition, the artist might not mix the clay and use a piece of Ox horn
to smooth out the clay and make it super smooth almost polished
looking or anywhere in between these two extremes.
Therefore, these textures are not typical characteristics of any
specific clay.
Ring tones can depend on the firing temperatures of the pot, different
clay thickness and if the pot is wet from use. Honestly, the ring
tone has nothing to do with the quality of the pot. I know this will
be argued but it is true. The main reason for the ring check was to
see if the teapot had hairline cracks from misuse or a bad firing. It
is imposable to tell the quality of a pot by the ring due to all of
the different factors involved.
In fact some teapots are fired a bit lower on purpose some say they
just have a different feel to them that seems to some, more
comfortable.
So now, you ask how to tell good clay? Honestly, if I write too much
here some fly by night Teapot Vendor will copy years of experience
paste it on their website and claim they know everything there is to
know about Zi Sha. When I finish my website 100% I will have tons of
encrypted hard to copy information for all to read and enjoy.
If you are interested in getting an e-mail from me when I have this
kind of detailed information available then e-mail me and I will put
you on a list and send you a link when I am done (one day I hope). I
plan to have a ton of information about Puerh, Zi Sha, and other
things that most vendors will not tell you.
All of the above information is my view from my experience, it is not
set in stone, and I am not here in hopes of selling anything. I am
only sharing my little but sometimes-useful knowledge about these
things. I will never to claim to know everything about anything!"
As you already know the rabbit hole keeps going deeper and deeper...
