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Author Topic: Naturally speaking, Opal, 'To potch or not to potch'  (Read 939 times)

mehoose

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Naturally speaking, Opal, 'To potch or not to potch'
« on: July 28, 2022, 10:56:47 AM »
Now, here lies the question.I was always taught that for an opal to be considered a solid and worthy of the title, that it was to have no potch on the base whatsoever.Wind forward 10-15 years, now there's videos streaming with folk leaving the potch on the back, which as we know, will enhance the colour most times but they're still claiming it as eg, a solid black and they seem to be valuing them at the top price per carat.(Or do I have that wrong?)

What the what? ??? ??? ??? ??? ???
In the day, I was told that an opal with potch still attached(we're talking potch already there, not glued on) was called a natural doublet.

A true solid opal that has no natural potch I've now heard referred to as a black crystal.Who's rewriting the accepted?Where do we now find, facts as accepted by all the Gemmo affiliations as the standard to be followed?
While I'm on the subject of Opals, years ago there was system that you could purchase where you'd enter the details of your opal in, body tone, brilliance, dimensions etc and it would give you the basic rate/real time as to ballpark figure of that specific opal. Is this still available, has it been renamed?
And it would seem we can pretty much call the pattern within our opal something new if it doesn't fit the norm.
Here's a question, what is it called when there's an image of something within the stone that has formed naturally? like Jesus on the cloth for example? I have seriously forgotten the name.
Keep em comin!!!

mehoose

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Re: Naturally speaking, Opal, 'To potch or not to potch'
« Reply #1 on: August 14, 2022, 10:33:13 AM »
Anyone here into the opal entries for the Gemboree comps? So maybe club members who oversee the collation of club entries..or even if you judge entries yourself , that would be brilliant.
I've been listening to a bunch of videos trying to get a handle on what is true/correct for both comp and for selling opals to the general public and to collectors.
I'll start with the clubs.At the local club, we were instructed that we had to remove all potch and sand from everywhere, top, sides and back. That to leave any potch on would deem it
  • A doublet
  • Lower the value
  • Not a solid opal
  • Increase the chance of the opal cracking over time due to different expansion rates.
  • earn demerit points in a comp situation.
In vids from Ridge miners/cutters and I think on opal Auctions they have a different opinion.To leave potch  and sand in bottom half only,
  • Proves natural state
  • Is called a solid.
  • Is called a natural opal and what gives it the classification of being for example, a LR Black Opal, Dark Opal, Light Opal. N1-N9
  • Higher value(yes, dependent on tone, brightness and pattern)
If the potch gets removed, it's then called a Crystal opal
Then you have Boulder Opal and White.
With Boulder, Koroit/Yowah, host rock makes it what it is.
With the White opal, what happens if that has host rock or white potch?
I've read it lowers the value and needs to be removed and is also a potential opal cracker down the track.
What is the truth? Are the club comps working on outdated info or the members within the clubs working on outdated info?
I'd love the thoughts of ALF members and if opal cutting is your business, please weigh in.


Keep em comin!!!

Bucket

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Re: Naturally speaking, Opal, 'To potch or not to potch'
« Reply #2 on: August 15, 2022, 11:59:13 AM »
Interesting question Mehoose. Having not entered comps, I've never really thought about it but my understanding was that a doublet was just that, two pieces glued together, a triplet was three pieces. The solids I've seen produced on YouTube ideally with black opal, have black potch on the back. I saw one recently where the colour was very thin but had a lovely black potch layer and the he valued the stone at around $3000 per carat because of the potch, he also mentioned that it would be $4000 per carat with les potch on that back. They seem to refer to black opal with the potch as black crystal opal and generally has colour right through it. I'm sure AFLACA will have some definition in their rules and regulations, but not sure as I'm not forking out the dollars they want for the booklet unless I start to cut for comps.
Common sense isn't exactly common

mehoose

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Re: Naturally speaking, Opal, 'To potch or not to potch'
« Reply #3 on: August 15, 2022, 01:06:29 PM »
Hi Bucket, yep and I'm confused even further because I have now seen a vid where the potch was completely removed but it was still called a solid but not a crystal because you couldn't see through it.  :-\ I am devo'd(devastated) that a couple of ripper opals were made too thin by us being told we had to take the potch and a couple of sand spots off the back of a few, making them too thin in my opinion to be set into jewellery.
Keep em comin!!!

Bucket

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Re: Naturally speaking, Opal, 'To potch or not to potch'
« Reply #4 on: August 15, 2022, 09:48:33 PM »
As far as setting into jewellery, I have cut some opal with irregular backs, I just used some scrap silver to pack it on the thin side and used a fully backed bezel setting, worked a treat!
Common sense isn't exactly common

dom105

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Re: Naturally speaking, Opal, 'To potch or not to potch'
« Reply #5 on: September 13, 2022, 07:29:16 PM »
While we're talking opal, just got back from the Ridge and what a let down.  The gene pooped itself, so no jack pick, just a hammer and chisel.
Was very social though as a mate came up, so did a friend of Lesley's and guy's from the BB lapidary club.
Thermal pool every afternoon and then sitting in front of the fire and telling tall tales.

mehoose

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Re: Naturally speaking, Opal, 'To potch or not to potch'
« Reply #6 on: September 15, 2022, 05:25:31 PM »
Sometimes the unwind is needed more than production. Thermal Pool would be very welcome down this end today. I'd rather be damp and warm in a pool than feeling damp and cold inside the house.
Hope the gene isn't too xy to fix.
Keep em comin!!!

dom105

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Re: Naturally speaking, Opal, 'To potch or not to potch'
« Reply #7 on: September 16, 2022, 08:04:01 AM »
Believe it or not the gene was an Aldi special and has lasted about eight gruelling years. So at about $600 I think I may have got my monies worth out of it. I'm not aware of any spares available for Aldi gene's either so it may be time to let go and let it RIP.

 

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