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 Post subject: Yowah Opal
PostPosted: Thu Nov 02, 2006 9:51 am 
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I was wondering if anyone has heard of Yowah opal from Queensland Australia? i saw some on ebay, but have not heard of it before. any info is greatly appreciated. Also, is lightning ridge considered the best black opal?

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PostPosted: Thu Nov 02, 2006 10:57 am 
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it is boulder opal, where a spot of colorful opal is surrounded by the iron stone, like an egg-yolk surrounded by the egg white. Lightning ridge is famous for black opal, I'd heard it is pretty well mined out though, others will varify that, or not, will subsiquent posts.


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PostPosted: Thu Nov 02, 2006 12:15 pm 
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Lightning Ridge definitely produces the best and most black opal in the world. I work with people directly on the field and can assure you it is by no means mined out. Production from all opal fields is spotty depending on the prevailing market price and new discoveries. New "hits" always seem to come along -- especially when prices are high!

It should be mentioned that ironstone/boulder opals can have black backgrounds and such stones are properly graded as black opals too. The colors -- and prices -- on such stones can be incredible. Since boulders come from Queensland as well, you might say that state has the corner on the world's black opal although blacks are found elsewhere in Oz and around the world.

As for Yowahs, also from Queensland, I like Richard's description of the precious opal being like an egg yolk. Or think of them as ironstone "nuts" with a kernel of precious opal inside the brown shell. They're found only near the Queensland community of Yowah and in fact are often called Yowah Nuts. When cut or split they can reveal amazingly bright and beautiful precious opal. Fine ones are rare and costly.

Rick Martin


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PostPosted: Thu Nov 02, 2006 12:56 pm 
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I have many boulder opals from Yowah and Koroit (another region that produces similar material), and they can be quite lovely. The prices for top quality material should be substantially less than for top quality Lightning Ridge material, as boulder opal simply doesn't fetch as much. Still, it can be outstandingly attractive, and I would highly recommend the material.


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PostPosted: Thu Nov 02, 2006 2:29 pm 
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gem-n00b wrote:
I have many boulder opals from Yowah and Koroit (another region that produces similar material), and they can be quite lovely. The prices for top quality material should be substantially less than for top quality Lightning Ridge material, as boulder opal simply doesn't fetch as much. Still, it can be outstandingly attractive, and I would highly recommend the material.

It's important to be specific here. Above I was referring to the very finest red-on-black or red-multicolor-on-black boulders, not the light opal colors. Top black boulders are valued virtually the same as top non-boulder blacks.

A price check with The Guide shows an extra-fine red-orange Lightning Ridge black 8 to 15 carats will retail for $20,000/ct.+ in the current market while an extra-fine boulder of 10 to 15 ct. is priced exactly the same. Top boulders in sizes above 30 ct. can retail for $80,000/ct. and more, and I'm sure individual non-boulder blacks of large size can as well. In this range of quality stones are valued individually and the rule books can be thrown out the window.

If I can get a decent image I'll post an interesting Koroit rough I'm preparing to cut. It shares characteristics with Yowah and will be difficult to classify for sale.

Rick Martin


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PostPosted: Thu Nov 02, 2006 3:11 pm 
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Well, once you get to the world-class-gem range, all bets are off, obviously. My point was simply that (in the price range of normal mortals) if you wanted a natural Lightning Ridge black opal with the colors and fire that are in the small seams of some top Koroit/Yowah, you'd need to spend substantially more money than if you were to buy the ironstone matrix material.


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PostPosted: Thu Nov 02, 2006 3:41 pm 
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gem-n00b wrote:
Well, once you get to the world-class-gem range, all bets are off, obviously. My point was simply that (in the price range of normal mortals) if you wanted a natural Lightning Ridge black opal with the colors and fire that are in the small seams of some top Koroit/Yowah, you'd need to spend substantially more money than if you were to buy the ironstone matrix material.

Hi Noob,
I'm not talking "world class" in all cases. If you read my original statement carefully you'll find it says:

"It should be mentioned that ironstone/boulder opals can have black backgrounds and such stones are properly graded as black opals too. The colors -- and prices -- on such stones can be incredible."

You saw fit to take exception to that comment, which contained no misstatements or distortions of fact. I merely responded with real-world pricing. Do you have any cites or facts to the contrary?

Rick


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PostPosted: Thu Nov 02, 2006 4:23 pm 
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I think we may be talking about different things. To my understanding, "boulder opal" can mean both the Yowah/Koroit type material with thin veins of precious opal running through an ironstone matrix... as well as large "plates" of precious opal on an ironstone "backing"... sort of a natural doublet. I'm speaking of the former, not the latter. Maybe some pictures would help, I'll try and rustle some up.


Last edited by gem-n00b on Thu Nov 02, 2006 4:32 pm, edited 1 time in total.

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PostPosted: Thu Nov 02, 2006 4:29 pm 
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This is what I mean when I talk about Yowah/Koroit-type (although there are MANY different patterns out there, this is one easy-to-visualize example):

Image

As for the other kind of boulder opal, there's also this type:

Image

It is my understanding (based on my personal experience purchasing opal both online and at gem shows) that while the latter example would be priced essentially as black opal (with perhaps a slight discount on weight, if there is a substantial amount of ironstone backing), the former (while every bit as beautiful in its own way, IMO) is simply in another price category altogether. I didn't mean to imply that fine boulder opal (the second piece) was substantially less expensive than black opal... it's not, as you rightly point out.


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PostPosted: Thu Nov 02, 2006 4:34 pm 
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Speaking of high-quality boulder opal, anyone want to venture a guess what this beauty might bring on today's market? ;)

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PostPosted: Thu Nov 02, 2006 5:12 pm 
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Noob,
You're posting 'em faster than I can keep up. Yes, there's a misunderstanding but not on my part. You're not grasping that boulder opal which faces black IS black opal. It's not considered a natural doublet. It's valued exactly the same as black opal from any locality.

To quote Anthony Smallwood FGAA, GG, Chairman of the Opal Nomenclature Subcommittee of the Gemmological Association of Australia Ltd., writing in the Australian Gemmologist (1997):

"If the tone of the opal appears darker than N4, then the opal may be classified a black opal. Consequently, any opal with a body tone darker than N4, irrespective of hue, can correctly be termed black opal. Some boulder opal possesses this body tone, so it is very correctly termed black boulder opal. It is also appreciated tht some very dark red Mexican-type opals would have dark enough body tones to be categorised as black opal."

That's exactly what I said more concisely above. I said nothing about other non-black boulder opals, with which I am very familiar. The attached image shows about 20 pounds of rough Koroit waiting for me to cut. One piece has an exposed pattern similar to the Koroit piece you posted above. The rest contains seams and patterns of various qualities. I've processed thousands of carats of all kinds of opal: light, dark, black, nobbies, seam, verticals, boulder, matrix, Yowahs, Mintabe blacks and others. I'm pretty familiar with all opal varieties.

I can't post it but if you wish to see a top black boulder of the kind I referenced above, go to page 46 of "Australian Precious Opal: A Guide Book for Professionals" by Andrew Cody of Andrew Cody Pty Ltd.

Rick

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PostPosted: Thu Nov 02, 2006 5:22 pm 
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Sorry if I misunderstood. I thought that boulder opal and black opal were distinct in that boulder opal had an ironstone backing/matrix whereas black opal had a dark potch backing/matrix.

As far as them being "doublets", I didn't mean in the artificial sense, simply that there was precious opal on top of another substance.

Looking back over the thread, I notice something that I missed before. You assumed that I took issue with your comment, "It should be mentioned that ironstone/boulder opals can have black backgrounds and such stones are properly graded as black opals too. The colors -- and prices -- on such stones can be incredible."...

But I didn't take issue with it. I explained that I was talking about Yowah/Koroit pieces whereas you were talking about boulder opals that are also black opals. I apologize if you thought I was trying to correct/contradict you, but I surely wasn't.


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PostPosted: Thu Nov 02, 2006 5:51 pm 
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gem-n00b wrote:
Sorry if I misunderstood. I thought that boulder opal and black opal were distinct in that boulder opal had an ironstone backing/matrix whereas black opal had a dark potch backing/matrix.

As far as them being "doublets", I didn't mean in the artificial sense, simply that there was precious opal on top of another substance.


I think Smallwood's statement clarifies your first point.

For your second, about the "doublet" question, see the Cody book where it is stated: "They are considered solid opals..." Also see Fred Ward's wonderful book "Opals," which I believe every opal-fancier should read.

Ward writes: "If you have precious opal atop either common opal or another substance, is it a doublet? Not if they formed naturally together..."

This is not to say assembled boulder opal doublets don't exist! These forgeries are quite common and I've seen some that are extremely well made. They are often hard to detect even when you know what they are.

Speaking of boulder opals, here's an image of some Brazilian boulders I saw recently in Idar-Oberstein, Germany. Sorry about the image quality: I was shooting with flash through the glass display case.

Rick

Image


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PostPosted: Thu Nov 02, 2006 5:58 pm 
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ROM wrote:
I think Smallwood's statement clarifies your first point.


Yes, Rick, that's why I used the word "thought" in my last post. I was indicating what I HAD previously thought to be the case until I was corrected. I KNOW Smallwood's statement clarifies it... hence my acknowledgement above.

ROM wrote:
For your second, about the "doublet" question, see the Cody book where it is stated: "They are considered solid opals..." Also see Fred Ward's wonderful book "Opals," which I believe every opal-fancier should read.

Ward writes: "If you have precious opal atop either common opal or another substance, is it a doublet? Not if they formed naturally together..."


I used the phrase 'sort of' a natural doublet... indicating that I was using the term more to conjure an image rather than as a trade term. I am aware that there are assembled boulder doublets, I own quite a few. I don't know why you take issue with the phrase "natural doublet" though, surely it has descriptive value?


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PostPosted: Thu Nov 02, 2006 6:26 pm 
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gem-n00b wrote:

Yes, Rick, that's why I used the word "thought" in my last post. I was indicating what I HAD previously thought to be the case until I was corrected. I KNOW Smallwood's statement clarifies it... hence my acknowledgement above.

Sorry if I overemphasized. I was trying to be comprehensive, not rude.

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I don't know why you take issue with the phrase "natural doublet" though, surely it has descriptive value?

Sorry again for overemphasis. Yes, it's descriptive but I think it's also misleading, especially in light of the "genuine doublets" we're both familiar with. Precious opal terminology is very confusing to begin with, especially with so many different conflicting terms in trade and common use. I'm certainly not any kind of final authority but I try to base all my descriptions on the system described by Smallwood here:

http://www.opal.asn.au/nomenclature.htm

Rick


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