Editor’s Note: Some years ago, the International Gem Society (IGS) conducted a survey of members’ gemstone polishing techniques. In this article, you’ll find the results for polishing gems in the 7-8 hardness range. This range includes very popular jewelry stones, like emerald, quartz, spinel, topaz, and some garnets like malaia and mandarin. 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.

Polishing Techniques for Gems of 7-8 Hardness

Laptype Polish Lubricant Votes
Tin Linde A/Aluminum/Cerium Oxide water 19
Tin 50-100k diamond oil or water 17
Ceramic 50-100k diamond oil 13
BATT 50-100k diamond oil or water 8
BATT Linde A/Cerium Oxide oil or water 6
Lucite 50-100k diamond oil or water 5
Dynalap Cerium/Aluminum Oxide water 5
Last Lap 14-50k diamond oil 4
Lucite Cerium/Aluminum Oxide soapy water 3
Turbofan water 3
Copper 50-100k diamond oil or water 3
Tin Linde A oil 2
Cast Iron 100-200k diamond bort olive oil 2
Ultra Lap Aluminum Oxide

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