tumbling

gem cutting

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Last updated

July 14, 2026

Quick Summary

Tumbling is a method used to polish gemstones, particularly those with a Mohs hardness of 7 or less, such as agate, opal, and jasper. This process involves placing the stones in a rotating cylinder with abrasive grit and water. The cylinder's rotation causes the stones to become polished, though their final shape is irregular.1

This technique is one of several ways gemstones are treated for jewelry. Other methods include cutting en cabochon (a rounded upper surface with a flat underside) or faceting, which involves precise cutting to enhance brilliance through light refraction and reflection.1

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gemstone
…7 or less) may be tumbled; that is, they may be placed in a cylinder with abrasive grit and water and the cylinder rotated about its long axis. The stones become polished but are irregular in shape. Second, the same kinds of gemstones may instead be cut en cabochon (i.e.,…
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…7 or less) may be tumbled; that is, they may be placed in a cylinder with abrasive grit and water and the cylinder rotated about its long axis. The stones become polished but are irregular in shape. Second, the same kinds of gemstones may instead be cut en cabochon (i.e.,…
Read More