Instructions for Tumbling Gemstones
Gemstones are small polished pieces of certain rocks and minerals which yield a beautiful luster after tumbling. Some rocks that produce jewelry-quality gemstones are: chalcedony, opal, rose quartz, tiger's eye and turquoise. Gemstones are polished by processing in a rotating or vibrating tumbler filled with abrasive grit, water and the stones. Rough edges are reduced by tumbling in progressively finer abrasive grits and polish. Tumbling may damage porous, fragile and brittle stones such as celestite and obsidian.
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Things You'll Need
- Tumbler
- Tumbling media (broken rocks)
- Water
- Coarse abrasive grit
- Clean cloth
- Medium abrasive grit
- Fine abrasive grit
- Polishing compound
- Grated bar soap
Instructions
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Tumbling With Coarse Grit
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1
Examine the tumbling media -- broken rocks, also called tumbling rough -- for any fractures, pieces with voids or stone of severely irregular formation. These should be discarded or broken up. The stones should be of uniform hardness. The sizes may be different.
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2
Dismount and open the tumbling barrel. Fill it halfway to three-quarters full of tumbling media.
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3
Put coarse grit into the tumbling barrel in a ratio of 2 level teaspoons to 1 pound of stone. Check the manufacturer's instructions for ratio variance.
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4
Add water to the mix until it almost covers the stones. The water level should just touch the bottom of the upper layer of stone.
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5
Use a clean cloth to clean the seal. Close the tumbler and check to be sure there is a good seal. Remount the barrel.
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6
Run the tumbler for a week. Check periodically for leaks and proper operation.
Tumbling With Progressively Finer Grits
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7
Dismount and open the tumbler over a bucket.
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8
Wash the tumbled rocks and the barrel with clean water.
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9
Examine the tumbling media and remove any rocks with imperfections that need to be re-tumbled in coarse grit. If the stones are to be used in gardening rather than jewelry, you can skip this step.
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10
Use medium grit and repeat the process outlined in Section 1. Tumble for a week.
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11
Repeat the process as described in Section 1 using fine grit. Tumble for a week.
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12
Use polish and repeat the process as described in Section 1. Tumble for a week.
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13
Use grated bar soap to burnish the stones. Repeat the process as described in Section 1, but tumble for a few hours. Remove your finished gemstones.
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1
Tips & Warnings
Tumblers are rated as to capacity. Weigh your load to keep it within the machine specifications.
Tumblers come in two forms, rotary tumbler and vibrating tumbler. The rotary is faster. The vibrating tumbler does a better polishing job. Start with a rotary machine and add a vibrating machine later, if desired.
Mild bar soaps, grated with a cheese grater, are best for burnishing.
Do not dump used tumbling water and washed grit down the drain. The grit can clog the drain.
References
- Photo Credit Liquidlibrary/liquidlibrary/Getty Images
