Filling a crack in a moonstone

[SueS11184]

Someone brought me a moonstone ring (moonstone with black tourmaline, there’s quite a bit going on in it), the stone has a very fine hairline crack - you can’t really see it, but you can just barely feel it. I’m wondering if there’s a way to fill it? Thanks.

[jeffg-moderator]

Other than epoxy, I don’t think there is anyway to fill it. Unless the stone is going to fall apart it’s often best just to leave it as is.

Jeff

[SueS11184]

I didn’t know about epoxy, so I’ll look into that, thank you. It’s not going to fall apart though. Cheerio

[rmeixner]

Look at Opticon. I have never used it, but others have and they may have some suggestions…Rob

[SueS11184]

I googled it and all the results were for hearing aids and eye stuff…

[rmeixner]

Then you probably googled oticon.

[SueS11184]

No, but that’s what Google gave me. Oticon, and also Opticon but it’s a scanner. I just tried adding different things to the word opticon and finally hit pay dirt with “opticon resin”, since I assumed it must be a resin or something Thanks.

[rmeixner]

Here is a link to an old Orchid discussion…Rob

Opticon?

I have seen mention of Opticon on Orchid previously, but I don’t know much about the product, or its use in the trade. Someone has brought it an old piece of jewelry, and the center is a large, flat cabochon (38mm X 27mm X 5mm thick) of highly included peridot with a number of cracks in it. Would Opticon treatment do anything to minimize the obvious cracks, or is there another way of dealing with it (besides putting it in the trash, that is) and, is there an Orchidian with experience with…

[jeffg-moderator]

Rob, Thanks for posting that thread! I was surprised though, though that a large percentage of folks who have used Opticon, either weren’t happy or described it as a difficult material to work with. It looks like it’s epoxy resin. Folks talk about soaking stones in acetone, vacuuming it & baking it to 150 F. It sounds fairly technical, (compared to hardware store two part epoxy resin).

It’s impossible to tell without looking at this particular stone, but I still think if you have a thin crack in a cabochon stone, that it doesn’t look really horrible and there’s no danger of the stone falling apart in a bezel setting that it’s probably best to leave it be.

Again, there’s no one correct answer. That’s just probably what I would do. I often take the path of least resistance.

Cheers!

Jeff

[SueS11184]

Thank you. The moonstone reminds me of a clear sky with wisps of cloud, plus the black tourmaline bits, so the very fine crack is not visible at all. I’ll just leave it.

[rmeixner]

That’s why I have never used it…Rob

[jhaemer52]

I’ve used Opticon on a number of occasions. It is made by Hughes Associates. Tim and I usually use it on damaged opals, emeralds etc. The procedure that has worked best for us is the following.
First clean and then soak the stone in acetone. Then pour enough of the fracture sealer in a small container to cover the stone. We then place it in our vacuum pump and vacuum it for several seconds at 30 PSI. It then gets placed under a warm lamp and left overnight. The next morning the stone is removed from the sealer bath and allowed to cool to room temp. and wiped dry with a a paper towel. A couple of drops of the hardener is added and wiped onto the stone. Let it set for about 15 mins. Then it is towel dried as well. And finally, if the piece is to be sold the treatment must be disclosed to the purchaser.
Jo

[jeffg-moderator]

Thanks Jo! This is great to know about.

Jeff

[rmeixner]

Thanks Jo. There are also youtube videos that demonstrate this process very clearly…Rob

[kennajmccall]

I wouldn’t use Opticon or any ither resin because they could show up yellow against the blue-white of the moonstone. Moonstone often has inclusions. I would wear it until it cracks, if ever.

[MichelleG12891]

Opticon is an optically clear epoxy used by gem crafters for years. Some stones have hairline fractures so we “stabilize” the stone material before cutting and polishing. This is for gemstone cabochons like your moonstone. Sometimes, after a stone is banged around in rings and bracelets, they develop cracks and chips that can turn into cracks. Opticon can be used then as well. Opticon has a part A that is absorbed by the stone with heat or time. Just use an incandescent bulb over your stone and let the epoxy seep in for hours. You then paint on part B where the cracks are and let it set up for at least 24 hrs before polishing the stone.

Here is a link to the product: Opticon Fracture Sealer and Hardener - RioGrande

[SueS11184]

Thanks. I’ve now watched some videos about it. I’ll get some, though I can’t get it from Rio, since they won’t ship it to Canada. I think my local rockhound shop probably has it though.

[Brennan-AG]

Amazing. Thank you!