How to Polish Gems of 7-8 Hardness: Survey Results

Spinel - Sri Lanka
Spinel has a hardness range of 7.5 to 8. These beautiful gems make excellent, durable jewelry stones in many colors. Prior to the 20th century, many spinels were identified as rubies or sapphires. Spinel, Sri Lanka, 4.93 cts. Photo © Joel E. Arem, PhD, FGA. Used with permission.

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 …

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