How to Make Polished Stones
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Select stones that are have mostly rounded edges because they are easiest to polish.Siri Stafford/Photodisc/Getty Images
Select rocks that are appropriate for this process. Many types of rocks will polish easily, but this process will not work on certain varieties. As a general rule, stones that are already mostly round or that have a slight shine to them will work best. - 2
Use a household pen knife to easily determine which rocks are best for polishing.Stockbyte/Stockbyte/Getty Images
Scratch the surface of a stone with a pen knife to test it for hardness. The harder the stone, the more easily it will polish, so do this test for each stone before attempting to put it through the polishing process. If the knife creates a harsh powdery line on the stone, it will most likely crumble during the polishing process and should not be used. If the knife leaves a thin, metallic, colored scratch on the surface, the stone is strong enough and is appropriate for polishing. - 3). Set up your equipment, using your tumbling kit's instruction manual, to start the first leg of the polishing process. Fill the tumbling barrel three-quarters full with the stones you selected and then shake gently the barrel to settle them. Pour water into the barrel, over the stones, until it comes just over the top of the stones. Add 1 1/2 tbsp. of 80-grit coarse silicone carbide. Turn on the machine and allow the rocks to tumble for two whole days.
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Pour out the water in the barrel in between tumblings.Jupiterimages/Comstock/Getty Images
Open the tumbling barrel and empty the water. Rinse the stones of grit and place them back in the barrel. Refill the tumbler with water to just over the surface of the rocks. Add 1 1/2 tbsp. of 220-grit silicone carbide. Replace the cap on the tumbler and restart the machine. Allow this second tumbling to continue for five whole days. - 5
Finished stones have a resilient shine and a smooth, round shape.PhotoObjects.net/PhotoObjects.net/Getty Images
Drain the barrel, rinse the stones and refilling the barrel with water as before to prepare for the final tumbling period. Add 2 tbsp. of 400-grit silicone carbide. Replace the cap on the tumbler and restart the machine. Allow the machine to run for a full seven days to finish the polishing process. When complete, the stones should have a distinct round or oblong shape and a resilient shine.
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