How to Shape a Gemstone

Gemstone shaping is an important skill that every jewelry maker eventually must learn. Usually, beginning jewelry makers use pre-carved stones so that they can focus on the metalworking techniques. But this limits your ability to design a unique piece, because you must design around the shape of the gemstone that you have. A jewelry maker who can carve gemstones is free to make any conceivable design, later conforming a gem's shape to the design parameters.

Things You'll Need

• Gemstone
• Paper
• Pencil
• Assortment of grinding wheels
• Hanging motor or fixed mandrel grinder
• Safety goggles
• Olive oil
• Fine-grit sandpaper

Instructions

1. Lay the gemstone on top of a sheet of paper, and trace it with a pencil to get the basic shape. Using this guide, draw your planned shape for the gemstone from a few different angles so that you can see how much material needs to be removed.

2. Set up a safe, convenient workspace on a table or jeweler's bench. Place all your equipment and your design drawing on the table, and put on a pair of safety goggles.

3. Attach a rough grinding wheel to your grinder. Hold the gemstone in one hand and the grinder in the other, and turn on the grinder.

4. Grind down the surface of the gemstone lightly, all over the piece, to get a clean surface. Grind the gemstone into a rough approximation of your overall design shape, following the design drawing.

5. Turn off the grinder, and replace the rough grinding wheel with a medium-grit wheel. Grind down the surface lightly again, working out the rough texture made by the previous wheel.

6. Locate the largest imperfections in the gemstone surface. Move the grinding wheel over these imperfections carefully, working them down.

7. Replace the medium-grit wheel with a fine-grit wheel. Repeat Steps 5 and 6 with the new wheel, this time grinding down the smaller imperfections as well. Turn off the grinder.

8. Rub olive oil into the surface of the gemstone. Look over the stone to see if the oil has revealed any hidden imperfections, then grind out these imperfections with the fine-grit wheel.

9. Tear off a strip of fine-grit sandpaper, and dip it in water. Rub the sandpaper all over the gemstone, working down the tiniest imperfections and scratches.

Tips & Warnings

• You need to plan your design around any cracks or defects in the gemstone, because these spots need to be ground down. In some cases, you will not be able to grind out a defect without removing a great deal of stone material.

• You can attach your sandpaper to the grinder, in order to make the sanding process go faster.

References

• Ganoskin: The Complete Gem and Jewelry Making Information Resource

Resources

• The Getty: The Art of Gem Carving