Fine sand casting suppiers?

[Konstantin]

Hello.
Some while ago while I was reading about sand casting I found this provider that offered this sand capable of getting very fine detail, some clay-sand or something. Have anyone seen this type of casting sand?

This casting sand was expensive.
I know this post is vague, but anyway.


Thank you.
Konstantin.

AutoResponse:
Ok I found it, Delft Clay.

Later.