How Do I Polish Tourmaline and Garnet?

By far, the best way I have found to polish both Tourmaline and Garnet is with a Tin lap and Alumina Oxide (AO2). Or a Phenolic lap and AO2.

I use a high grade alumina oxide polish, with about 1 tablespoon polish to 2-3 tablespoons of water in a slurry (a small amount of vinegar can be added to help stop scratches, although it is seldom a problem). I apply the polish to the lap with a decent quality watercolor paint brush that is made for applying washes (it holds a good amount of liquid/polish).

Run the lap just fast enough that it does not throw the polish off, and keep the stone moving in a nice sweeping arc.

 

I personally think that a Tin lap definitely works better with the lap scored, than it does without. I find that the scores help keep the polish on the lap longer, which speeds up polishing and also seems to help remove waste from the polishing process.

Do I really need to score polishing laps and if so how?

If you have not used a scored tin lap before, it feels a little strange to start with, but it really works.

Note: You can polish with or without scoring.

Note2: I prefer having 2 Tin laps (I cut and polish a lot) one for Tourmaline and one for Garnet. Garnets are slightly harder than Tourmaline and I have occasionally had a Garnet chip cause scratching problems on Tourmaline. It is rare though.

Note 3: Occasionally I get a piece of Tourmaline that a Tin lap leaves very, very tiny horse tail types of scratches on. If this happens I touch the facets up with a Spectra Ultralap charged with AO2.

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