Keep some aspirin close at hand. You’ll probably need it.
Polishing Kunzite isn’t for Beginners
Step #1: Go to nearest wall and bang your head against it. Repeat as needed during cutting process. Important: Set the kunzite down before you bang your head. It’s shock sensitive and you may damage it. (The kunzite, that is).
I would tell most new faceters to move on to something easier instead of kunzite, the pink to purple variety of spodumene.
Kunzite Presents Challenges for Jewelry Use
Unless you’re looking for a challenge (and a sore forehead), kunzite may not be worth cutting. Kunzite’s color is UV light sensitive. With exposure over time, it will fade to colorless. It also has perfect cleavage, so it won’t wear well in jewelry. Only use it as a pendant stone or set it in a protective setting. If it’s worn much, expect to replace it sooner or later.
Due to color fading and poor wearability, kunzite has no real commercial appeal except for some collectors. Don’t plan on making money cutting it.
Polishing Kunzite Advice
So you still want that sore forehead? Here’s how I cut kunzite.
If you have to saw, use a high-quality thin blade and a saw with as little vibration as possible. Leave plenty of room from where you saw to where you want to cut the stone out of.
Fractures are very common after sawing. Therefore, wait a day or so before you start cutting for the fractures to appear. Then, cut them off with a fine lap.
You should cold dop kunzite. This is one of the few materials that I recommend it for.
Have a bottle of glue solvent handy, so you can unstick yourself from the things you touched while using glue. (For extreme cases, have a friend close by who can help you get unstuck after they finish laughing at you).
Orientation and Polishing
Orient your kunzite for the best color and cleavage plane(s). The C axis usually has the best color. It needs to be perpendicular to the table, but not quite (like topaz). This material has perfect cleavage, so you need to work it on a very fine lap. Use nothing more aggressive than a well-worn 600 or finer.
Any shock will cause cleavage separations and problems in general. Be gentle and patient. With a little luck, you’ll finish a kunzite. Polish it with an Ultra lap (Spectra or alumina), tin/lead lap with tin oxide, or a wax lap.
I know some gem cutters from Afghanistan who frequently work with kunzite. They tell me they use tin laps with 14,000-grit diamonds for a final polish. Their finished stones that I’ve seen looked quite well-polished.