Goodbye, Rough Rocks. Hello, Smooth Stones.
It takes years and years for nature and its elements - dirt, rock, water, and sand - to smooth a rock's surface. With a device called a rock tumbler, you can get those same results in considerably less time. A tumbler rolls or vibrates the rock over and over until the sharp edges and dull exterior are worn away, revealing a smooth, shiny surface.
Down to the Nitty Gritty
Rock tumblers use material called silicon carbide grit. Since the grit is harder than sand, tumblers can polish rocks much faster than nature. When tumbling, start with a coarse grit, move to a fine grit, then proceed to a silicon sand step. The final step is polishing with any variety of commercial polishes, including titanium dioxide (an ingredient used in toothpaste).
What Comes Around, Goes Around
Start by adding rocks, coarse grit and water to the tumbler barrel. Rock tumblers turn very slowly to allow the rock to "climb" the inside wall of the barrel. As the rock reaches the top of the wall, it tumbles down the other rocks and into the slurry mixture created by the grit and water. The next time around, the rock will carry the slurry with it onto other rocks.
Rocking and Rolling
Use a variety of rock sizes for best results. Small rocks are good for getting inside the nooks and crannies of larger rocks. A barrel that's too full won't allow enough room for the rocks to go down. A barrel that isn't full enough won't allow the rocks to "climb" the wall. And be careful how much water you add to the barrel - if too much, the mixture will be thin and the rocks will "float" rather than cascade down.
Patience Produces Pretty Pebbles
Tumbling rough rocks into smooth stones is a step-by-step process with each step typically taking up to one week to complete. Step 1 rounds the rock. Step 2 removes deep scratches from the rock. Step 3 removes fine scratches. Finally, step 4 adds a glossy shine.