Miscellaneous Gems: Polishing Survey Results

Editor’s Note: Some years ago, the International Gem Society (IGS) conducted a survey of members’ polishing techniques. Here, you’ll find the results for some miscellaneous gems. These include popular stones, like beryl, garnet, and topaz, for which we unfortunately didn’t receive too much feedback. In addition, you’ll find more unusual gemstones like andalusite as well as lab-created materials like yttrium aluminium garnet (YAG). Whether you’re just starting to learn the art of gem cutting or just looking for a new way to tackle a problematic gem material, we hope these results provide some useful suggestions.

For more information about the survey or to find results for more gemstones, click here.

Looking for advice on faceting exotic gemstones? Click here.

Polishing Techniques for Miscellaneous Gems

Andalusite

• Lap: BATT.
• Polish: Linde A.
• Lubrication: Oil.
• Speed: 200.
• Pressure: light.
• Quill Motion: slow sweep.

Beryl Gem Family

Copper Lap

• Polish: diamond paste.
• Lubrication: Crystalube.
• Speed: 400-600 rpm.
• Pressure: light, medium.
• Quill Motion: slow.

Proprietary Epoxy Paper

Scored radially

• Polish: cerium oxide, except emerald. For emerald, use acid soluble tin oxide that you can remove from open fissures with hot nitric acid.
• Lubrication: H₂O+20/10 concentrate dispensed

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