The mold is called a "Spirit" mold, but is also known as the "Sprint" mold. The chips are called "china clays" as they are manufactured in bulk in china. There are a few retailers that sell them here in the US. Here is pics and the site that i have seen has them listed:

http://www.chipsandgames.com/tricolor10gramnometalinsertclaychipsforcolorinserts.aspx

PGI also sells "China Clays" but on a different mold.