pectolite - 4-6 hardnesspectolite - 4-6 hardness

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.

3 Minute Read

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 apatiteWhether 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


Ultra LapAluminum/Cerium Oxidevinegar/water19
TinLinde A/Cerium Oxidewater15
LuciteCerium Oxide/Linde Awater13
WaxAlumina/Linde A/Ceriumsoapy water/water7
DynalapCerium Oxidesoapy water/water7
Spectra (Ultra Lap)Cerium Oxidewater7
Lucite50k diamondwater6
BATTLinde A/Cerium Oxidewater5
Tin100k diamondvinegar/water3
Tin50-100k diamondoil2
Copper50-100k diamondCrysta Lubrication2
CDCerium Oxidewater2
PhenolicAluminum/Cerium Oxidewater2
Spectra (Ultra Lap)Colloidal Silicavinegar/water2
Raytech Fast LapCerium Oxidewater1
Raytech Fast Lap50k

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