That’s crazy! (No pun intended) I just worked on a HUGE stone filled with cracking, crazing and potch lines. Honestly it taught me a lot about the differences between the 3 and how to spot them. In the end it made the biggest stone I’ve ever made at just under 44 carats with multiple patterns including script pattern. It is still in the observation stage in case any cracks pop up that I’ve missed but so far so good. The stone was contained in a beginner’s parcel as a gigantic blob of sand and was certainly an anomaly. While beginner opal cutters will eventually have to tackle stones with cracking and crazing eventually, I agree when the time comes they should ease into it with a not so overwhelming stone full of problems.
Good thing you had the skills to salvage what sounds like a pretty decent chunk of opal. Let hope both our stones stay strong and hold themselves together.
Great video, mate, thanks for sharing! I wanted to offer a couple of thoughts, maybe ideas to explore in future videos, especially since your audience likely includes a lot of new opal cutters. I think that we can all agree that being an opal cutter is all about taking rough, sandy, cracked, or imperfect material from the ground and transforming it into something beautiful and stable. Every opal field produces material with some degree of cracking, sandy inclusions, and other imperfections. Part of the craft is learning to identify these, understand them, and plan your cuts accordingly. I wonder if telling new cutters not to buy material like this gives them the false hope that somewhere out there exists some perfect material that has no issues with it at all. Maybe it lives with the super cheap black opal harlequins and really affordable flagstone patterns, but I've never seen that! When working with material like this from Coober Pedy (I'm about 95% sure it is CP), another approach that addresses these potential pitfalls is to face it first (as you demonstrated with the 80-grit), then dry it out completely, a very common practice among commercial opal cutters. Once dry, the cracks become much more visible. From there, you can draw them in with a sharp mechanical pencil and plan your cuts to work around the cracks, aiming for a few smaller but perfect stones rather than risking cracked finished pieces. What you’ve done in this video is great in terms of technique, but is it possible that it could unintentionally reinforce the misconception about storing Australian opals in water and how not doing so will cause cracking. I know you’d never sell a cracked stone without addressing it, but many new cutters might follow this approach and sell a piece soon after cutting. If water has seeped into a crack, it can mask the flaw to the untrained eye. This was perfectly demonstrated in your video. In the beginning your sharpie seeped into the crack making it very easy to see, once the water fully penetrated the crack became essentially invisible. Once the opal dries (often weeks or months later), the crack becomes clear to see again, and this often leads to the mistaken belief that Australian opal cracks from “drying out.” I also wonder how my years as a cutter and the experience I got from the hands on cutting compares with the papers you reference in the video? In reality, the issue stems from not identifying and cutting out those cracks in the first place. I just wanted to flag this because I know you value educating cutters and wouldn’t want this to confuse those just starting out.
I dont think there is a perfect material for beginners but I know crazed stones ain't it. The number of people I've talked to that have quit after a certain bad seller (which you can probably guess) sold dozens of beginners nothing but crazed rubbish is insane. Thankfully talked one or two into trying again but most are out of the game for good and will just buy opal jewellery. "could unintentionally reinforce the misconception about storing Australian opals in water and how not doing so will cause cracking" Actually, the paper indicates the opposite, hence, why I store all Australian opal dry to minimise the chance of drying shrinkage and silica dissolution. The paper even talks about the possibility that changing storage water over time could make it even worse. "the issue stems from not identifying and cutting out those cracks in the first place" Sometimes. Sometimes not. With crazing, the post extraction storage can have a much greater impact in terms of decrepitation vs drying shrinkage vulnerability before it even gets in the hands of the cutter. Its a really interesting paper, and if it is free access, well worth reading for any opal cutter. Maybe I do make a video on this and a few other papers on the topic because some of the results are pretty surprising.
Well that’s a happy and rare surprise! I’ve only been able to rescue a handful of gems once they started to crack/craze. Hopefully, new cracks don’t develop. Good luck!
I was equally surprised. Honestly the aim of the video was to show it fall apart and... it failed. Maybe I need that aim for every stone if they work out this well. Now to keep an eye on it for a year.
That was perfect for me right at this time. I have been thinking about looking for crazed and cracked stones, just to get a bit of affordable stone with colour to look at. I have bought a lot of beginner parcels and have some pieces with colour but they have been very thin and small, so far. I'm wondering now, would you consider using that stabilizer liquid on a crazed or cracked stone? Thanks for all the helpful and well made videos, Roy. I really look forward to watching them all.
I dont like stabilizing any stone other than a fairy opal or loose Adamooka matrix. It can certainly be done and I might show how on a piece of cracked potch but it just effects value to much for me to bother.
Fantastic show using different burrs for different effects. Q. You said very little cirrium oxide is used but I can't see how it's applied. Do you get a wet polishing burr and just dip the burr into dry oxide and polish? I guess, given the amount of nothing in your wet tray. I just love the training Roy. I've got my new Vevor SR set up but haven't used it yet, kind regards Paul BB FNQld
I bought a couple of ounces of LR opal with crazing. Apparently the miner had let is sit in a shipping container for 40 odd years. We used it to train my daughter to cut and polishing. We have salvaged a lot of the stones and yes, we have put them aside to ensure that they don't contain to craze. We are not prepared to stabilise the stones as we are purests in that regards.
Wow- this was a timely video indeed! I’m working on a stone atm & CANNOT get a smooth polish on it…. I’m about to go back for the 3rd time- but it seems to remain slightly bumpy as light moves across it under magnification- & not a nice glassy polish. Could this be due to fine, webby crazing?
If physically bumpy there might be a different issue. It should still be pretty smooth when crazed if you keep seeing white lines that could be crazing.
One thing I can say is be careful with them, if you end up having to use a lower grit sintered diamond bit, sometimes the vibrations can aggravate a crack so if you haven't spotted it prior you may end up with 2 pieces.
Which databases would you go to for scientific research about opals? Or are there some nice scoping reviews of the field? Would be fun to just get an idea what type of research people are doing :-)
There are AI tools that are incredible now at finding papers of about any topic. If I had them during my PhD I could have saved months of searching. Being part of a uni I get free access to just about everything but for free even just google scholar can do a lot of heavy lifting.
I would avoid it like the plague. Iv had some bits just fall into multiple bits not worth doing anything with. I know Pulitzer Opal keeps all his cut and polished opal in water. So it might be interesting to see some scientific advice on wet or dry opal.
The paper defines it pretty well "a phenomenon observed either in the form of whitening or cracking". A bunch of white lines that look like cracks but eventually they can form cracks if the crazing is bad enough.
That’s crazy! (No pun intended) I just worked on a HUGE stone filled with cracking, crazing and potch lines. Honestly it taught me a lot about the differences between the 3 and how to spot them. In the end it made the biggest stone I’ve ever made at just under 44 carats with multiple patterns including script pattern. It is still in the observation stage in case any cracks pop up that I’ve missed but so far so good. The stone was contained in a beginner’s parcel as a gigantic blob of sand and was certainly an anomaly. While beginner opal cutters will eventually have to tackle stones with cracking and crazing eventually, I agree when the time comes they should ease into it with a not so overwhelming stone full of problems.
Good thing you had the skills to salvage what sounds like a pretty decent chunk of opal.
Let hope both our stones stay strong and hold themselves together.
Thanks for the video Roy, much appreciated.
No worries as per usual Chad.
You done ✔️ a great job Roy.
Cheers 🍻👍⛏️
Thanks man. This one was mostly luck.
Interesting video. Thanks..
No worries. Hope it helps.
Great video, mate, thanks for sharing!
I wanted to offer a couple of thoughts, maybe ideas to explore in future videos, especially since your audience likely includes a lot of new opal cutters.
I think that we can all agree that being an opal cutter is all about taking rough, sandy, cracked, or imperfect material from the ground and transforming it into something beautiful and stable. Every opal field produces material with some degree of cracking, sandy inclusions, and other imperfections. Part of the craft is learning to identify these, understand them, and plan your cuts accordingly.
I wonder if telling new cutters not to buy material like this gives them the false hope that somewhere out there exists some perfect material that has no issues with it at all. Maybe it lives with the super cheap black opal harlequins and really affordable flagstone patterns, but I've never seen that!
When working with material like this from Coober Pedy (I'm about 95% sure it is CP), another approach that addresses these potential pitfalls is to face it first (as you demonstrated with the 80-grit), then dry it out completely, a very common practice among commercial opal cutters. Once dry, the cracks become much more visible. From there, you can draw them in with a sharp mechanical pencil and plan your cuts to work around the cracks, aiming for a few smaller but perfect stones rather than risking cracked finished pieces.
What you’ve done in this video is great in terms of technique, but is it possible that it could unintentionally reinforce the misconception about storing Australian opals in water and how not doing so will cause cracking. I know you’d never sell a cracked stone without addressing it, but many new cutters might follow this approach and sell a piece soon after cutting. If water has seeped into a crack, it can mask the flaw to the untrained eye. This was perfectly demonstrated in your video. In the beginning your sharpie seeped into the crack making it very easy to see, once the water fully penetrated the crack became essentially invisible. Once the opal dries (often weeks or months later), the crack becomes clear to see again, and this often leads to the mistaken belief that Australian opal cracks from “drying out.”
I also wonder how my years as a cutter and the experience I got from the hands on cutting compares with the papers you reference in the video?
In reality, the issue stems from not identifying and cutting out those cracks in the first place. I just wanted to flag this because I know you value educating cutters and wouldn’t want this to confuse those just starting out.
I dont think there is a perfect material for beginners but I know crazed stones ain't it.
The number of people I've talked to that have quit after a certain bad seller (which you can probably guess) sold dozens of beginners nothing but crazed rubbish is insane.
Thankfully talked one or two into trying again but most are out of the game for good and will just buy opal jewellery.
"could unintentionally reinforce the misconception about storing Australian opals in water and how not doing so will cause cracking"
Actually, the paper indicates the opposite, hence, why I store all Australian opal dry to minimise the chance of drying shrinkage and silica dissolution. The paper even talks about the possibility that changing storage water over time could make it even worse.
"the issue stems from not identifying and cutting out those cracks in the first place"
Sometimes. Sometimes not. With crazing, the post extraction storage can have a much greater impact in terms of decrepitation vs drying shrinkage vulnerability before it even gets in the hands of the cutter.
Its a really interesting paper, and if it is free access, well worth reading for any opal cutter. Maybe I do make a video on this and a few other papers on the topic because some of the results are pretty surprising.
Awesome video! Looks like the shape of my home state of Arizona USA.
I feel like I know the shape of all the USA states after watching the last few elections. Not much work got done that day.
Beautiful color
Surprised me more than anyone.
Nice stone and cool shape. Sand and cracks add more frustration as a beginner, but good to learn about these types. 😊
Certainly something that needs to be learnt in the end but good to walk before running.
Good topic
Tough one to beat though.
Well that’s a happy and rare surprise! I’ve only been able to rescue a handful of gems once they started to crack/craze.
Hopefully, new cracks don’t develop. Good luck!
I was equally surprised. Honestly the aim of the video was to show it fall apart and... it failed.
Maybe I need that aim for every stone if they work out this well.
Now to keep an eye on it for a year.
That was perfect for me right at this time. I have been thinking about looking for crazed and cracked stones, just to get a bit of affordable stone with colour to look at. I have bought a lot of beginner parcels and have some pieces with colour but they have been very thin and small, so far.
I'm wondering now, would you consider using that stabilizer liquid on a crazed or cracked stone?
Thanks for all the helpful and well made videos, Roy. I really look forward to watching them all.
I dont like stabilizing any stone other than a fairy opal or loose Adamooka matrix.
It can certainly be done and I might show how on a piece of cracked potch but it just effects value to much for me to bother.
That really did turn out nice I certainly would be interested in seeing a comparison between dry stored and water stored stones.
I might reach out to the researchers and see if any would be willing to talk. Otherwise I could just go through their findings.
Fantastic show using different burrs for different effects. Q. You said very little cirrium oxide is used but I can't see how it's applied. Do you get a wet polishing burr and just dip the burr into dry oxide and polish? I guess, given the amount of nothing in your wet tray. I just love the training Roy. I've got my new Vevor SR set up but haven't used it yet, kind regards Paul BB FNQld
You make a solution (1 teaspoon into 1 cup of water) and apply that to the stone as much as needed to keep it wet for the whole process.
Turn down to be a beautiful stone ✌️♥️
Yeah I was most surprised. I was just waiting for a crack to split. I'll watch it for the next year.
I bought a couple of ounces of LR opal with crazing. Apparently the miner had let is sit in a shipping container for 40 odd years. We used it to train my daughter to cut and polishing. We have salvaged a lot of the stones and yes, we have put them aside to ensure that they don't contain to craze. We are not prepared to stabilise the stones as we are purests in that regards.
You can get lucky and the crazing can stop. It does effect the outer most regions first so if you cut it away it can still be okay under the skin.
Wow- this was a timely video indeed! I’m working on a stone atm & CANNOT get a smooth polish on it…. I’m about to go back for the 3rd time- but it seems to remain slightly bumpy as light moves across it under magnification- & not a nice glassy polish. Could this be due to fine, webby crazing?
If physically bumpy there might be a different issue. It should still be pretty smooth when crazed if you keep seeing white lines that could be crazing.
Don’t you hate it when you plan for a crappy stone and cut a ripper gem. I feel for ya Roy 😂and 😂😂😂
Haha happens... almost never but this one really didn't want to prove the point I was hoping it would.
One thing I can say is be careful with them, if you end up having to use a lower grit sintered diamond bit, sometimes the vibrations can aggravate a crack so if you haven't spotted it prior you may end up with 2 pieces.
I dont mind to much, if it cant survive a good grinding I wouldn't want to set it and sell it anyway.
Which databases would you go to for scientific research about opals? Or are there some nice scoping reviews of the field? Would be fun to just get an idea what type of research people are doing :-)
There are AI tools that are incredible now at finding papers of about any topic.
If I had them during my PhD I could have saved months of searching.
Being part of a uni I get free access to just about everything but for free even just google scholar can do a lot of heavy lifting.
@RoysRocks true, I should have a look in Perplexity or something, would be fun :-)
I would avoid it like the plague. Iv had some bits just fall into multiple bits not worth doing anything with.
I know Pulitzer Opal keeps all his cut and polished opal in water. So it might be interesting to see some scientific advice on wet or dry opal.
The wet vs dry research surprised me so maybe it is really worth discussing... might need to put together a presentation style video for that.
Can ypu explain crazing please
The paper defines it pretty well "a phenomenon observed either in the form of whitening or cracking".
A bunch of white lines that look like cracks but eventually they can form cracks if the crazing is bad enough.
@RoysRocks can you add a link to this paper please... I feel like my level of noobness is showing through 🤣
Nice results Roy hope she don’t crack up later m8 🫡👍
Only time will tell. I hope it doesnt but if it does it'll be back on the channel straight away