Description: Polish rocks for your own collection, or make crafts and jewelry for your friends and family with the Rock Tumbler from Smithsonian. This tumbler uncovers the secrets under the surface of ordinary rocks, revealing amazing colors and patterns with a glass-like finish. Just place a few rocks in the tumbler with some of the included grinding powder. Then, select the number of days you want the rocks to tumble. Choose one day for a little shine, choose four days for a lot of shine. Comes with Rock Tumbler and Craft Kit.