Tumbled and polished rocks have been very popular with hobbyists and collectors for generations! Tumbling brings out details not apparent on a rough stone. Finished stones can be collected and traded, or used for beautiful jewelry, mosaics, and crafts. You can find interesting samples along stream beds or at the beach.
The process is quite simple. Place rough mineral or rock in a cylindrical (barrel shaped) drum and add a rough grit of silicon carbide. As the barrel rotates, its contents collide, wearing down the stones (where they would naturally erode in time).
A stone-tumbling machine can be found in most hobby or lapidary supply shops. They range in price from about $20.00 for a very inexpensive, child’s model, to $700.00 for serious, industrial uses.
A tumbler consists of an electric motor (in the old days, it was done manually), a barrel, and a frame with rollers. A pulley and a belt connect the rollers to the motor.
To begin, fill a four pound or less barrel almost three quarters full with stones of about ¼ inch to 1 inch in diameter. Add a rough grit of silicon carbide (approximately ½ pound for every 2 ½ pound load, adding water to cover. Every day (wait approximately 24 hours), stop the machine, remove 10 stones and wash them under clean water. Then allow them to dry and inspect them with a small magnifying glass under bright light. If they are pitted or cracked, return them to the tumbler and continue. When your samples do not reveal these pits, cracks and hairlines, remove all the stones.
Clean out the sludge in the barrel. Wash the stones and the barrel well as the process will be repeated a number of times. Sort for imperfect stones, and place the good ones back in the barrel with other rough-ground (or polished) stones until the barrel is almost three-quarters full again. Add again the right amount of grit and water, and repeat the process. Check it daily. Some stones may take up to a week before they become perfectly smooth. Once done, ensure the stones are well cleaned, and clean up your barrel.
Now, for the final part. Return the stones you have tumbled into the barrel for polishing! Add 1 tablespoon of cerium oxide for every 2-3 pounds and just cover with water. Tumble for up to one week until the luster of the rocks is high.
Once highly polished, remove from the tumbler, and clean the tumbler and stones as before. Return them to the barrel for a final time with half a teaspoon of detergent (laundry is fine), and water to cover. Tumble a final 6-8 hours to remove the remaining film from the stones.
Rinse extremely well and dry and store in a soft cloth or chamois.
Your rocks are ready for use in jewelry and artwork! Use silver or gold wire to “cage” the stone and attach to a chain or rope for a beautiful, one of a kind necklace and, learn to identify and classify individual rocks.Your rocks
This hobby is fun for all ages!