Removing polishing marks from stones

I recently ran into this issue where somewhere along the finishing process for this ring, scratches were introduced to the face of this garnet. I have no idea how this happened, as I prepolish before setting, and the “tripoli” I use (Luxi yellow) never scratches my stones. Does anyone know how this may have happened? Low quality stone filling came off during ultrasonic maybe?

And is it possible for me to polish these out? Pretty upset as the ring was coming out great until I noticed the scratches at the final step.

Those scratches look too deep to just polish out. Unless that is just a trick of the picture, the top will have to go through a grinding and sanding process before it is polished. Garnet isn’t super hard. Was it loose in the ultrasonic basket to maybe scrub around on the metal mesh? We have recently discussed how to fix a damaged stone that is in place. Search on it to see if you find anything useful…Rob

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I dip rings in my ultrasonic with a plastic hook so that wasn’t it. My only guess is if those scratches were filled with resin or something and it came out during ultrasonic cleaning. The scratches seem way too coarse for a treated wheel. It’s just strange because they are only on the face and none of the facets.

I’m curious about yellow Luxi, I use blue instead of Tripoli and like it.

I like it a lot. I don’t know how it compares to blue as I haven’t used it, but yellow is pretty aggressive if you lay into it, and gentle if you don’t. I use it after an 800 grit luxor wheel before final polish, or after the red eveflex bits. You can do it after the grey but it’s not as precise.

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Those grooves are pretty deep… unless the stone was cut defectively and filled, the only other possibility is that there was something hard in the buffing wheel or buffing compound… tripoli has a moh’s hardness of 5-7, garnet 6.5 -7.5…there’s an overlap, depending on the garnet, with almandine being the hardest at 7.5 - 8… Pyrope has a hardness of 7. since the grooves are parallel, they could be due to some hard foreign material in the buffing wheel… fragments of file steel have a hardness of 6.5 -7…it could cut grooves, or if there’s any aluminum oxide (hardness 9) or silicon carbide (9.5) dust or particles from contamination with other abrasives. In general, garnets are pretty hard, but anything less than quartz (mohs 7) risks getting worn down, more than scratched by tripoli… I’ve used white tripoli to polish cabochons that I cut and ground out of raw turquoise and other soft stones…

The grooves could be polished out by a lapidary… If it were due to buffing, I wouldn’t trust trying to buff it out… even if you changed to a new wheel, you could get scratches again, especially if your tripoli was contaminated…

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I actually just came across this in a ring that I was doing some work on. I wasn’t paying attention when I was using my sanding discs and I wasn’t cleaning between each sanding disc so as I finished with one type and moved up to another and I was wiping my the stuff off of the stone and ended up scratching the top of the Stone. Also managed to do it a little bit once before with my polishing disc even though it was very very soft cloth it still put marks on the stone.