The Rolling Stones Rock Tumbler has Many Original and Unique Features which will make it Easy and Pleasurable for you to Start the Fascinating Hobby of Rock Tumbling and Jewelry Making. New $44.49 (17% off). Recommended for ages 10 and over. Features: * Each cycle will use a different type of grit (Coarse Grit, Medium Grit, Fine Grit, and Polish) Each individual package is marked. * Red plastic barrel is turned by a rubber drive shaft. * Barrel will turn 50-80 revolutions per minute. * Machine tumbles rough semi-precious rocks into finished gemstones. * Semi-precious stones (Agate, Jasper, Amethyst and others) plus jewelry parts.