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Author Topic: Opal Doublets, what are they?  (Read 489 times)

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Bluetangclan

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Opal Doublets, what are they?
« on: January 24, 2018, 05:44:51 AM »

This should be an obvious answer since I have made them and try keep my rough stock up to the point I don't have to dig into my chips because they are a pain to make(I think). But having a discussion with some Aussies on facebook and I have discovered that I think our two nations have different definitions of what a doublet is.

To me, its basically when you have an opal that has great color(not wasting my time on just an ok one) but it is too thin to stand on its own so you find some black jade glue it on and go. Once done now you have a structurally sound piece of opal which likely had its color heightened by the black backing of the jade, however now it will sell for about a tenth of what a similar sized solid opal would be, but hey, better than nothing. But basically salvaging a nice colored opal that's too fragile by itself.

From what I am getting from the Aussies, they consider anytime you change the color of the backing or paint the back of the opal or essentially anytime you do anything involving the back of the opal, its a doublet. Even blackening the inside of the setting or putting a booster pad to make it stand a little higher in the setting, but not actually attaching the opal to it.

This came up because someone posted the pic of a fairly nice 20.11ct black crystal opal they picked up somewhere and some of the Aussie guys were telling the dude to turn it into a doublet and that got us to arguing about it(because that's what facebook is for) and me realizing we weren't exactly talking about the same thing when we used the word "doublet."
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hummingbirdstones

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Re: Opal Doublets, what are they?
« Reply #1 on: January 24, 2018, 06:06:41 AM »

I just did a search and didn't see any definition of doublet that indicated that a doublet was anything other than a stone being bonded to a lesser value stone to make it usable (including Aussie sites).

The facebook guy is being overly anal and an idiot.
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Robin

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Re: Opal Doublets, what are they?
« Reply #2 on: January 24, 2018, 07:05:18 AM »

I hope some of our members from Oz weigh in here. Painting backs is an "enhancement", but the trade terminology for "doublet" always meant two separate pieces of opal (or other backing material) attached to each other to create a single piece.

There are also people who refer to "natural doublets", but that would include any seam opal with natural potch or matrix remaining underneath the color bar. Also not what the accepted terminology has always been.

There is an old thread in the archive somewhere discussing this - at some length, if I remember correctly.

rocks2dust

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Re: Opal Doublets, what are they?
« Reply #3 on: January 24, 2018, 10:12:35 AM »

I agree, painting the back is enhancing (the only reason is to change the color characteristics), but it is ridiculous to class things that do not alter the stone itself (adding to a setting that has a dark backplate, or putting on a pad to raise it in the setting) as treatments or enhancements - the stone itself remains an unaltered, solid opal in those cases with nothing adhered to it.

The "natural doublets" may or may not be worth mentioning. If the back "matrix" is opal, then the stone remains a solid opal. If the back matrix is some other sort of stone, then that does affect carat weight and should be mentioned (it is not a manufactured "doublet" however). Many solid opals have precious tops and potch backs; they are still considered solid opals and priced accordingly.

Doublets do not always detract from the value. For example, I've seen some hyalite opals bonded to other gemstones that made for higher prices than both would have brought, had they each been cut as solid gems. Depends on the opal.
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r2d

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gemfeller

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Re: Opal Doublets, what are they?
« Reply #4 on: January 24, 2018, 11:03:12 AM »

Just to clarify one of R2d's comments about natural doublets:  boulder opals (opals with natural dark ironstone backing) are considered solid opals.  In their highest grades they are valued in the same price range as fine solid black opals.

I don't know if anyone but me pays any attention to it but the Australian Opal Industry Council in conjunction with the Gemmological Association of Australia has issued a new opal nomenclature paper.  Under the heading of Composite Natural Opal they define doublet opals as: "...a composition of two pieces where a slice of natural opal is cemented to a base material." 

Since these are definitions developed by the Australian opal industry they should bolster your argument with your Aussie friends.
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Bluetangclan

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Re: Opal Doublets, what are they?
« Reply #5 on: January 24, 2018, 02:15:50 PM »

Pretty much what I have been thinking. Thanks for the actual definition there Gemfeller.
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hummingbirdstones

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Re: Opal Doublets, what are they?
« Reply #6 on: January 24, 2018, 04:45:50 PM »

Do you have a link to that paper, gemfeller?  Thank you!
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Robin

vitzitziltecpatl

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Re: Opal Doublets, what are they?
« Reply #7 on: January 24, 2018, 05:43:38 PM »

gemfeller

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Re: Opal Doublets, what are they?
« Reply #8 on: January 24, 2018, 07:47:52 PM »

Yep, those are the Smallwood links I was referring to.   Thanks Vince, saved me the trouble of digging them up.
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Sapphireminer

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Re: Opal Doublets, what are they?
« Reply #9 on: January 31, 2018, 03:47:51 AM »

Hi everyone I am no expert on opal but my take on a doublet is the same as already stated when a dark backing is glued to the opal to enhance the colour  hence 2 pieces or double add a clear top to the stone as well (eg quartz) 3 pieces making it a triplet . I dont no were colouring the back of stone fits in but I guess in the same area as silver foil under a faceted stone to enhance reflection .
Dave
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