How to Polish Gems of 4-6 Hardness: Survey Results
Polishing feldspar, fluorite, apatite, or other gems in the 4-6 hardness range? Our IGS member survey results can recommend some techniques and supplies.
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Editor’s Note: Some years ago, the International Gem Society (IGS) conducted a survey of members’ gemstone polishing techniques. Here, you’ll find the results for polishing gems in the 4-6 hardness range. Stones in this range include species such as feldspar, fluorite, and apatite. 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 4-6 Hardness
| Laptype | Polish | Lubricant | Votes |
| Ultra Lap | Aluminum/Cerium Oxide | vinegar/water | 19 |
| Tin | Linde A/Cerium Oxide | water | 15 |
| Lucite | Cerium Oxide/Linde A | water | 13 |
| Wax | Alumina/Linde A/Cerium | soapy water/water | 7 |
| Dynalap | Cerium Oxide | soapy water/water | 7 |
| Spectra (Ultra Lap) | Cerium Oxide | water | 7 |
| Lucite | 50k diamond | water | 6 |
| BATT | Linde A/Cerium Oxide | water | 5 |
| Tin | 100k diamond | vinegar/water | 3 |
| Tin | 50-100k diamond | oil | 2 |
| Copper | 50-100k diamond | Crysta Lubrication | 2 |
| CD | Cerium Oxide | water | 2 |
| Phenolic | Aluminum/Cerium Oxide | water | 2 |
| Spectra (Ultra Lap) | Colloidal Silica | vinegar/water | 2 |
| Raytech Fast Lap | Cerium Oxide | water | 1 |
| Raytech Fast Lap | 50k |
…
International Gem Society
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