Create incredible, polished rocks, gemstones, and minerals with the National Geographic Hobby Rock Tumbler! This expansive set contains a heavy-duty tumbling machine and rubber tumbler barrel. A programmable timer ensures you get the perfect tumble time. You also get one pound of rough rocks to tumble, 5 jewelry settings, tumbling grit, and a detailed learning guide with instructions. Learn all about the fascinating way rocks are polished in nature, how gemstones are used in jewelry, and much more in the full-color learning guide.
- BLUE MARBLE