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Polishing Goldstone

Hi all,

I’m looking to see if anyone has information on polishing goldstone. I’m having little success with diamond polishing paste, and after doing some research and reading that glass is best polished with Cerium Oxide I ordered some paste and powder with an average micron of 1.2 to see if that works.

The goldstone we’re using is a cab in a silver bezel setting. We’re using multiple sizes and are trying to avoid touching the goldstone with our buffs, but when we polish our 10mm settings there is some contact made by the buff every now and then. This puts a haze on the goldstone. The stone also seems to have a coating applied to it from our vendor. We learned that if steam comes in contact with the goldstone, it leaves a matte finish on the stone. We’re assuming this might be due to the factory coating being removed from the steam. We started using diamond paste with a felt wheel to limited success. Next step will be trying the cerium oxide.

If I could get some input on a few things it would be greatly appreciated:
-How firm of a felt wheel should we be using? We have “hard” on hand, but it seems to periodically be leaving flat spots on the cabs. I’m assuming a soft felt wheel would be better.
-Does anyone have any experience on polishing goldstone cabs, and what advice could you offer?

I appreciate any input. First time posting, long time reader.

Goldstone is basically glass with copper and other “stuff” in it. As far as I know, it is manufactured and doesn’t occur naturally. Try polishing with cerium oxide. You can use small felt wheels mounted on a flexshaft. I think that Moores makes a small felt disc too. Repolishing a damaged stone while still in the setting is a chore. You can’t really get to the area closest to the bezel which is probably where the damage is. I don’t know about the coating. It could be resin, museum wax or some other substance to make it look nicer than it will be when the coating wears off. Next time try covering your stone with masking tape. I cut off a small amount and then burnish it over the stone, especially around the area where the stone meets the bezel, and then cut out the excess with a sharp razor. Polish and then pull off the tape. This isn’t so much a problem with harder stone. There are also pumice discs that are supposed to be stone safe. I guess that it depends on how soft the stone is.Good luck…Rob

Thanks for the info Rob. Do you have any experience with coating stones? I don’t think we’ll put our own coating on the goldstone since we’re instead putting our effort into giving the stone a high polish, but it would be good to know regardless.

Nope, all my stones have a natural finish created by polishing with traditional abrasive polishes…Rob

I would add that I have tried filling pits and voids in cabs with various resins and waxes without much success. I have filled bezel cups with colored doming resins. As long as the finished surface is allowed to cure undisturbed, it makes a nice alternative to lapidary. Polishing resin can be tricky. Finally, I have finish ground, sanded and polished some softer stones while in the bezel and finish polished both the metal and lapidary with ZAM. Lots of experiments, but the best way to go is a lapidary stone in a setting that is carefully polished so as not to damage the stone. Good luck…Rob

I appreciate it Rob. I’ll check back after I get this cerium oxide in and let you know if it helped.

So we experimented with the cerium oxide and a soft felt buff. At first we were having little success, but after some more time we discovered that we just needed to keep the buff really wet to create a slurry for the cerium oxide polishing compound to work. We ended with a glossier shine than what the stones have from the factory. After doing this, we’re able to use the ultrasonic and steamer just fine. It takes the coating off of it, but I believe it will help in the future to prevent repairs coming in due to the coating getting cloudy from everyday wear and tear.

This is what we ended up using: Glass Polish 14006 Fine Grade Glass Polishing Compound, Professional Glass Polishing Solution, 16.9oz

Hello Patrick,
You have learned what all faceters know…that there is a sweet spot where a slurry is just wet enough and that when you get the buff too dry you get scratches. You can buy “crayons” of cerium oxide polish from Gearloose (google him) that will not scratch because of the wax medium or you could make your own by adding cerium oxide to Trewax, which is a hard paste wax with a high percentage of carnauba wax in it. Then you need not worry about keeping the slurry wet. You can find it in hardware stores and perhaps on line. And, yes, it produces a brilliant shine on glasses, silicas and quartzes, as well as some other gem species. -royjohn

royjohn! Thanks for all the info. If I were to make the cerium oxide hard paste was as you’re describing. Can I use that as I would a standard polishing compound on a felt buff. I.e. just apply it directly to the buff while it’s spinning?

I like the idea of the hard paste because then I’m not having wet cerium oxide slurry splashing all around our polishing stations.

And what’s the best way to combine the cerium oxide powder with the Trewax?

Hi Patrick,
You know, I never have thought of using it that way myself, but I suppose it would work. You would just put some wax…maybe a tsp or so, on a surface and sprinkle the cerium on top and then mix it up…I think a felt buff would need a lot more than a polishing pad, which doesn’t have so many soft folds to it, so I’d probably use a felt, pellon, cotton or similar polishing pad on a flat lap and apply the cerium impregnated wax to that. But I don’t see why an impregnated buff wouldn’t work. You have cerium already, so all you’d need to get to make the experiment would be a can of the Trewax. I see it for $13.99 on prime at Amazon. Just a lot more efficient to use a polishing pad, if you have such on your cabbing machine. I would mix in a good bit of the cerium, altho’ you may find that just a little is all that is required. Let us know how it works…-royjohn

When I use this cerium/wax, I use a very little water drip, but you can see if it works without it. With the pad you can use a spray bottle for just a little wetness…IDK how this would work with the felt buff…maybe just damp? You’ll have to experiment and see. -royjohn

So I picked up the Trewax from the hardware store down the street. took a slice of it and put it into a beaker on a hot plate. When it was melted enough, I sprinkled some cerium oxide powder in there and mixed it up. I then poured it into a small 1"x3" plastic container and put it in the freezer. I’ll test it out when it’s done solidifying. Hoping this works!

royjohn is right, lapidary is more art than science. You have to keep trying until you find what works. There are a lot of variables and what might work with one piece of Jade, as an example, won’t work with another. Keep notebooks and write down what works. Be sure to date your entry and give some context like where you got the material or from whom, what you did with the finished piece and who might have purchased it. Lapidary is fun, but it can also be very frustrating. If you don’t already know of them, take a look at the Kingsley North online catalog…Rob

While I agree with Rob that there are many little twists in lapidary, particularly with materials that tend to undercut, cerium oxide for glass, silicas and quartzes is pretty much 100% effective. That said, I do wonder how well the cerium and wax will work with no water at all…-royjohn

Cerium Oxide in a slurry with a crystal pad or felt pad works for me. If you are using a flexshaft, you are limited in what type of media you use. There are felt wheels and Moores type discs that can be flexshaft mounted and charged with polish. I haven’t explored Jool Tools yet, but they look interesting. Again, lots of alternatives to traditional lapidary available to us…Rob

So I mixed the cerium oxide with the carnauba wax and applied it on the felt buff to polish the goldstone with it. Unfortunately, it too needed water added to achieve a high polish. Thanks for all the advice.