Found it in their birthday party store:
Activity - FOSSIL, MINERAL & GEMSTONE EXCAVATION BLOCK
BPS-1EX
Click Image for details ..
A REAL FOSSIL DIG AT YOUR PARTY CAMP SCHOOL OR SCOUT MEETING. Find Genuine Dinosaur Bone, Shark Teeth, Petrified Wood, Crinoid Stems, Brachiopods, Amethyst, Citrine, Emeralds, Rubies, Topaz, Tourmaline, and lots more. Dinosaur Birthday Party Supplies.
OurPrice: $65.00
Price has gone up, but it would still be worth it if you were planning to spend money on an activity. We just had the dig in the backyard, dino relay races and cake. I believe they also have a gemstone excavation block.