Recommend a Glue for Broken Stone?

Jewelry Discussion
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Can anyone suggest a good glue for an opaque stone that has broken? Thanks, in advance, for recommendations.

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Take a look at Opticon. I have only ever used it once and it left a bit to be desired, but you will find it in most of the places that we buy tools and metal. I suspect that I didn’t use it correctly. You might talk to the techs about it. I might just try a CA glue or 2 part resin. Some resins can be polished…Rob

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Rob, I know this topic has been discussed before, but when I have a bezel set stone that breaks in a two piece clean break I just use epoxy. This would be for a repair, not a brand new piece.

Is there a reason to not use regular old two part epoxy to repair a bezel set opaque broken stone?

Isn’t Opticon mainly for transparent or translucent stones? I’ve never used it.

Thanks!

Jeff

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I too would likely use epoxy or CA glue. I just mentioned Opticon because it is out there. I think that you are correct that it is more for transparent stones and works as a filler for fractures. My thought is that the stone could be glued together towards the bottom and then fill the void with Opticon. The only time I ever used it was less than a success, but that was probably me using it for the first time…Rob

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Greetings-i use superglue. It takes a nice shine.

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I would highly recommend that you do the following.
First place some two sided tape to a surface that mirrors the bottom of the stone. Place the two parts together on the tape.
Then bend over, and pay the money for Opticon. It’s expensive but totally worth the price.
We have used it for decades with great result on both opaque and transparent stones.
We ignore the written instructions and do the following
Place the stone that is being held together in a small container that is high enough for the part A to cover the stone. We like to use small watch tins. Then place the container in a vacuum jar and vacuum up to 30 lbs pressure for a few seconds. Release the vacuum and put the stone still in the container in a warm place over night. We place ours under an old light fixture with the bulb about 6 inches away. In the morning remove the stone, (still on the sticky tape), from part A. Wipe the stone down with a paper towel. Then add a drop or two of part B and rub it in and then wipe it dry. Let it sit for a little bit and then remove the tape from the bottom. And finally if you are selling the stone be sure that you disclose that the stone has been treated.

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Thank you for this! I’ve tried to use it, but it hasn’t been as effective as I’d hoped so I’ll try this method.

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Akfix. I use it for dopping roughs. Will hold forever.

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I’m so grateful for this info! So innovative! When I’ve tried Opticon in the past, I followed the instructions to a T but never with success. I tried slight alterations, such as longer heat time, but it never worked.

The last time I tried Opticon, after following the instructions, I was so frustrated the next day that I put the stone up on my soldering stand with a piece of foil over the wire, got out my heat gun and applied heat gradually from underneath, hoping gravity would pull the Opticon down into the crack. I then took the foil back to the goose-neck light and let it cool gradually under the light bulb. Nope.

It never filled the cracks well or created the protective covering I was hoping for.

I unsuccessfully scoured the internet for adaptations in the use of Opticon. I picked the brains of lapidary and metalsmith friends on how they repair cracked stones… my fav lapidary laughed and said, “I don’t!”

I never found anyone who successfully used and swore by Opticon for filling-sealing cracks. But I’d come across it often as a crack solution in all sorts of articles and blogs.

I usually ended up using Vigor epoxy or cyanoacrylate. And was never happy with the results.

So I gave up and have been telling customers that I don’t repair cracks. I encourage them to bring their piece in and they can go through the hundreds of stones that I have for a replacement.

But I don’t like giving up. It feels like failure. And I do understand the draw of a sentimental connection to a stone in its setting. So I want to figure this out!

Thanks for the new creative way to get Opticon to work. I’m going to practice this on some cracked stones that I’ve set aside just for this learning purpose.

Joyfully! Robin

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Please read my comment from July 2024 above. I have never had a fail with the off label technique described in my post. If you don’t have a vacuum pump that’s OK. Just let it soak a bit longer under gentle light bulb heat.
Jo

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I have only seen one person who ever routinely had great success with gluing stones.
she did the following when making composite gems or stabilizing a crack.
She would mix up the Opticon or epoxy and have enough to cover the gem in a small aluminum foil cup. Then she would put it into her vacuum chamber to remove all the air and bubbles. it drew the adhesive into the smallest cracks every time.
It was so long ago that I do not even remember her name now. But I can still see her doing it and teaching me about it.

Then when dry, she would carefully cut and repolish the gem to make it look great.

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I’m pretty sure that was me. I’ve posted that tip years ago and again just this last year for a stone that was broken in two.

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I just recently started gem stone faceting in 2025. The majority of faceters are using two part epoxy resin. Or dopping with wax. I also have years of experience working with ammolites (extremely fragile, flakey, brittle gemstones that require Opticon and epoxy resin to hold them together, they are the Baklava of gemstones).

When I started faceting, I started off with CA glue and two part epoxy resin, but I hated the waiting, the off gassing of VOCs, the mess, having to use even more chemicals to remove the dop, etc, etc, etc. I decided to give UV resin a try and it has met all my requirements in the studio.

I can dop a piece of rough without having to grind in a flat surface. I can go from dopping to faceting immediately without the wait, I can drop a 400ct dopped gemstone on a hard floor and it doesn’t pop off the dop, because the resin is very fluid (unlike two part), it can seep into cracks, fractures or be pulled in with vacuum. There are no bubbles generated because there is no mixing of the resin. There are minimal VOC being released, nothing that I can smell. If I don’t get the alignment perfect I can reposition any number of times until I get it correct. The shelf life (unlike two part epoxy resin) is infinite, it doesn’t expire after a year or turn yellow. I keep a little medicine cup with a bit of the resin from the bottle on my work top (protected from light of course) and the only time it has set up on me is when I accidentally shone the UV light on it. If you accidentally spill or make a mess with the UV resin, shining the light on it sets it up and you can remove it as a solid from the work area. I have used it as a fracture sealer for Ammolite.

In the attached video I am creating a doublet from rainbow Moonstone and white Corundum. Faceting can be very hard on gemstones because of the vibrations from the diamond grit on the lap. If light can penetrate the stone, you will be able to use UV resin with great success.

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For any doubters. Here is the 400ct rose quartz dop.