Rockhounds please help ... what is this?

[arlene_v]

No clue what these are. Tested with the Presidium and the needle doesn't even budge. Very shimmery blue and green.

At first I thought Paua shell .... what do folks here think? I'm just not sure because it seems to be quite iridescent.

Set in a heavy (over 11 grams) 14k pendant so I'm thinking it might be some sort of stone or shell rather than glass? Closed back not open setting.

Any ideas?

TIA

Taken under flash

[bwrighttwo]

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@hollyblue83 wrote:

Since they didn't react to the tester,most likely it is polymer impregnated synthetic opal from Japan/China. Gilson and other lab created opals respond to testing like natural opals.

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I must have pics disabled but,,,,this is accurate that if LAB they should react the same. 

[arlene_v]

thanks.

Just a quick question .... I haven't got a lot of opal jewelry and only have two items to test set with what are probably doublets or the opals described by holly (despite being set in 18k gold and 14k gold) 

Both I tested with the Presidium and the Presidium had the same non-response as when I tested the stones in this pendant. ie the needle didn't move.

Can anyone tell me what range opals test in with the Presidium please?

If anyone has opals and a presidium I would be most grateful if you could give it a whirl and let me know for future reference,or I might take my Presidium to a dealer I know who has real opals and test hers and see what the results are.

[bwrighttwo]

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@arlene_v wrote:

thanks.

Just a quick question .... I haven't got a lot of opal jewelry and only have two items to test set with what are probably doublets or the opals described by holly (despite being set in 18k gold and 14k gold) 

Both I tested with the Presidium and the Presidium had the same non-response as when I tested the stones in this pendant. ie the needle didn't move.

Can anyone tell me what range opals test in with the Presidium please?

If anyone has opals and a presidium I would be most grateful if you could give it a whirl and let me know for future reference,or I might take my Presidium to a dealer I know who has real opals and test hers and see what the results are.

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I am not sure how they react as I have never used one. There are so many ways to fool those things I would not trust their output. I guess I meant that a lab Opal should test the same as a natural because of their physical/mineral proporties.