Worth paying for certification or not ?

[FrenchPearl]

I'd recommend the other way around. That way the lab will have better access to the nuclei without obstructed views.

Humm, that's a good point. I was thinking to recommend certification after the restringing in order to have the picture on the certificate match the latest "format" of the necklace. Since there is always a risk that someone"change" the pearl during restringing, it seems to me that it was preferable.
And does the GIA do an X-ray to determine origin ?
Yet another decision to make.....

 

[FrenchPearl]

Also I think that as natural pearls have been in the press more so of late, dealers are more aware of them and this has brought more to auction.

I agree Helen ! I was looking for such a necklace for me last year, and it seemed to me the prices were higher. With a quick search, I could find 2 or 3 I would have splurged on last year... However, I think this one is special

 

[Lagoon Island Pearls]

And does the GIA do an X-ray to determine origin?

The will use Xradiography where practical. In this case, they'd likely capture views of the largest pearls and examine the structure between the drill holes and the surface. Not likely on the small ones though, because much of the nuclear material has been destroyed by drilling. Physically and possibly thermally.

They'll weigh those views with a number of other factors (ie) microscopy for structure, presence of calcite and protein thickness.

FWPs tend to have more calcite present and thinner protein layers than saltwater pearls. In general, this is why most marine borne pearls are more (deeply) lustrous than those from fresh water sources.

 

[Orient]

The will use Xradiography where practical. In this case, they'd likely capture views of the largest pearls and examine the structure between the drill holes and the surface. Not likely on the small ones though, because much of the nuclear material has been destroyed by drilling. Physically and possibly thermally.

Having some experience with having pearls tested and asking similar questions to labs I can clarify this point a bit more accurately. GIA will test ALL the pearls by real-time X-ray and decide on the ID of pearls based on the resulting structures obtained. Drilling is always an issue in pearls as it does remove structural evidence, but most of the time there is plenty of evidence remaining. It all depends on the size of the drill-hole in relation to the pearl being tested and I have seen some definite natural pearls with LARGE drill-holes that have come out of historical or antique pieces so drilling cannot always be used as an excuse NOT to issue a report. They have to weigh-up all the details and reach a conclusion. Sometimes undetermined calls may be given on one or two pearls if doubt exists, or proof is lacking or debatable. That's my experience for what it may be worth anyway ;-)