What Are Tumbled Stones? Tumbled stones are small, rounded, brightly polished pieces of rocks and minerals. They are made by placing rough rocks in a machine known as a rock tumbler, which tumbles them until their edges and surfaces are smooth and polished. They are also known as "polished stones," "tumbled gems," "baroque gems," "polished rocks," and a variety of other names. Many people enjoy tumbled stones because they are beautiful natural materials that have been given a pleasing shape and a bright polish. They are popular in jewelry, craft, souvenir, awards, collectibles, and New Age markets. Tumbled stones can be purchased by the pound at prices that just about everyone can afford. Their colorful appearance and interesting shapes have inspired many people to learn more about rocks, minerals, and gems.