I tried this out on the stone gravel from my yard and was amazed at how beautiful the stones turned out. I have made keychains and necklaces from the stones to give as gifts and the receivers were amazed that the stone gravel could look so beautiful after the treatment. The only downturn is the machine is quite noisy. I had originally placed it outside but had to move it into the garage when the neighbor asked if a pipe had burst. Putting it on a piece of Styrofoam helps the noise somewhat.