Tumbled stones have a smooth surface and pleasing colors. Stones may be tumbled by nature as they move down a stream path or hillside, smoothing their edges as they rub against other rocks. Professionals and rock enthusiasts use mechanical tumblers to polish rough samples for sale or personal use.echanically polished stones are those that are tumbled in a commercial rock tumbler or a flat slab polisher. You can purchase home versions of rock tumblers if you want to create your own tumbled rock from rough specimens. Mechanical polishers use a grit and water to smooth the stone edges and provide a shine.