Types of Rock Tumblers

Rotary Rock Tumblers

• These rock tumblers are the ones most rock hounds are familiar with. These machines have one or two barrels that hold batches of rocks to be polished. As the barrels rotate, the rocks rub against each other, wearing away the rough edges, just as the constant motion of ocean waves smoothes beach pebbles. The rock tumbler with two barrels lets you polish two different batches of rocks at the same time. These tumblers can be noisy unless you get rubber barrels.

Vibratory Rock Tumblers

• Vibratory rock tumblers work a bit differently than their barrel cousins. These machines have a bowl that holds your water, grit and rocks. Once covered and turned on, the bowl vibrates back and forth, causing the rocks and grits to rub together. Since the rocks don’t “tumble” as they would in a barrel, they won’t have smooth corners, but the flat surfaces of the rocks will be polished. One benefit is that vibratory rock tumblers can polish more fragile rocks, such as obsidian. They also use less grit and polish, and they take less time for each tumbling step. Since vibratory tumblers don’t sit on their sides, they are not prone to leakage.

Kid’s Tumblers

• A kid’s rock tumbler is a scaled-down version of the adult rotary rock tumbler, meant to polish about 1/2 cup of rocks at a time. These tumblers come in kits with a coarse grit, fine grit and a finishing polish. A few of the kits even have inexpensive mountings to make jewelry out of the finished stones. Kid’s tumblers usually have plastic barrels and can be quite noisy. They tend to wear out quickly after a few batches, but they do work long enough to see if your child has a true interest in polishing rocks. These tumblers are usually less expensive than the adult version.