Crystal Opals to back or not to back

Hi, a little canvassing of opinion here.

Where you have obviously thin bits of opal you think are still very attractive, you can make a doublet out of them. Fine.

Where you have a crystal opal that is thicker, say 2-3 mm, that could stand on it's own, are you tempted to make a doublet with a black base to bring out the colour, leave it 'as is', or is there a third option of just colouring the back of the stone dark?

Doublets must be declared as such, which is as it should be.

What is the accepted norm in the industry of colouring the back of a stone? Again, it would be declared as such, but what does it do to the value of the stone?

A solid crystal opal, vibrant colours with a dark ink / pigment on the back or the same opal without the ink / pigment; how would you value such stones? A naturally dark crystal of the same vibrancy would likely be more expensive but if a transparent crystal could be offered with a black back, would that detract from the value of offering it with no black back.

I suppose what I'm asking is will you depreciate the value of the crystal opal if you make the back black rather than add a traditional doublet back and is it 'acceptable'?

Or would you leave the option of the coloured back to the stone setter?!

Cheers,

Any treatment that changes the stone from natural must be declared, and will devalue the stone, that being said a small thin item that has little value will be in most cases increase in value if made into a doublet, because you have value added, I would not be using 3mm thick opal to create doublets, many stones will benefit from a silver or gold backing e.g. bezel mount with or without backing.
Colouring the back of a stone in my opinion would detract from it, I do not know any one who does this.
I would be entertaining other ways of presenting the stone
I am sure you will receive many other opinions

Colouring the back of Opals or blackening the settings is a common practice usually with a Sharpie or black nail polish or Los , It does greatly improve the look of some opals by making the colour really stand out , I agree with China , If you do this then it is best to declare it. As for value it shouldn't change the value because it is the same stone with or without the black . I wouldn't even consider pricing an opal higher just because I made it look better by colouring the back. I would leave it to the setter to decide whether they want to do it or not.

I haven't bought one where this has been done, although very often it is done when setting.
If you photograph them for sale on a dark background then leave it to the setter to choose that would seem more the normal thing to do ?

Many thanks for the comments and feedback...all very welcome!

I’m quite paranoid about not misrepresenting my work and of course declare any adjustments made. I’ve been left disappointed myself with rough before where even with good direct artificial light and a through wetting, what I’ve seen in front of me hasn’t really matched the photos or descriptions!
Thanks again,