Tumble Finishing

Tumble finishing, also called tumbling or rumbling, is a technique for smoothing and polishing the rough surface of relatively small parts. A rock tumbler produces tumbled stones through a process very similar to the natural action that forms sea glass or beach glass, and rock collectors and hobbyists commonly use the process to turn rough-collected stones into smooth, polished ones. A related industrial process used on metal parts, called barreling or barrel finishing, works on the same underlying principle. Tumbling is distinct from traditional lapidary work, which shapes and facets individual stones by hand rather than rounding a whole batch of stones automatically in a rotating barrel. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/