Tumbled stones are made in a machine known as a rock tumbler. The most commonly used rock tumbler is a rotary machine that turns a barrel containing the stones, along with abrasive grit, and water, for days and weeks at a time. As the rocks tumble in the barrel, the grains of abrasive grit get caught between the rocks and abrade off sharp points and edges. This first step modifies the shape of the rocks and moves them towards a rounded shape. In two subsequent steps, smaller-size granules of silicon carbide are used to smooth the surfaces of the rocks in preparation for polishing. Then, in the final step, a rock polish such as micron-size aluminum oxide is used to produce a bright, lustrous, polished surface on the rocks. The tumbling process usually takes a few weeks to complete in a rotary tumbler.

Many people purchase rock tumblers to make tumbled stones as a hobby. Their tumblers range from inexpensive plastic machines that are usually loud and produce poorly-polished stones, to more durable metal machines with rubber barrels that are used by hobbyists. These machines usually tumble a few ounces to a few pounds of rock.

Commercial machines, used by companies who produce tumbled stones as a business, are large enough to tumble up to two or three tons of rock at a time. These companies purchase their rough rocks and supplies by the ton and are able to produce tumbled stones at low enough prices that they can be sold at retail for lower prices than the hobbyist can ever compete with. For that reason, people who want tumbled stones are usually best served by purchasing them rather than trying to buy the rocks and supplies that they need and producing them in a small tumbler. However, many people enjoy producing tumbled stones as a hobby, and some of them are fortunate enough that they live or travel in areas where they can collect the rocks that they tumble instead of buying them.