I had contacted them a few years ago and they sent me a sample of their tokens with a small plastic capsule inserted in the center and it had a bunch of small faceted amethysts. I gave it to someone awhile back... Can't remember who. Here's the web site http://www.gamingjewels.com/about.htm

Reference the Black Diamond casino chips... They have a small diamond that you can barely see inserted in the graphic of the diamond.

If you scroll down on the cochips web page...
2783 Ore Cart/3 Men Numbered/ Diamond
Obsolete
150 Produced
Chip Issued in:1994 $25.00
2782 Ore Cart/3 Men Numbered/ No Diamond
Obsolete
100 Produced
Chip Issued in:1994 $25.00
2781 Ore Cart/3 Men Unnumbered/ Diamond
Obsolete
85 Produced
Chip Issued in:1994 $25.00