A Gem Dealer’s Journal: GIA’s Nicholas Sturman
Today we interview Nicholas Sturman, currently GIA’s senior manager of pearl identification globally who is based in Bangkok. Nick has over three decades of pearl identification under his belt and is here today to help us understand this very specialized part of the trade.
Asia Lounges: I believe that prior to asking specific question it may be of interest to clarify our topic a little. Could you please tell us more about pearls in general? What are they and how are they formed?
Nicholas Sturman: Pearls are one of the organic gems found in the trade. They are as popular, some would argue more popular than diamonds, and are often referred to as the Queen of Gems. They form in a variety of molluscs either naturally (without humans being involved in any way) or as cultured pearls (with humans being involved).
A general rule of thumb is that pearls found prior to the 1920s are more likely to be natural, the further you can trace them back the more confident you can be they are natural, while those post 1920’s could be natural or cultured. It gets a little more complex than that as there is
more than one type of cultured pearl.
In the trade you may encounter bead cultured pearls (BCP) and also non-bead cultured pearls (NBCP). To add to this you may also find a variation of the bead cultured pearl that are referred to as “atypical bead cultured pearls” (aBCP). Natural pearls form accidentally by natural mechanisms such as the “entombment” of foreign matter that penetrates the shell and finds its way between the shell and living tissue (mantle) or that finds its way into the mantle itself; or results from unknown biological processes within the mantle. BCPs form via human interaction with the mollusc and after conducting an operation within the gonad where a shell nucleus together with a piece of mantle from a donor mollusc (1st operation only) are inserted, whereas NBCPs form after humans insert pieces of mantle from a donor into a host’s mantle. That leaves the aBCPs where a similar process is followed to the BCPs or, should an existing Pearl sac exist after the initial BCPs are produced, another bead (usually another shell nucleus, but could be any atypical material such as a natural Pearl or even a gemstone) is inserted.
Read entire article here: https://www.asialounges.com/blogs/a-gem-dealers-journal/a-gem-dealer-s-journal-interview-with-a-a-gem-dealers-journal-pearl-master-gia-s-nicholas-sturman-span-class-apple-converted-space-span?fbclid=IwAR0e6loE6Q24SjjhB72PddiFKkTr67SEK9fLgWf73MDhhkYVLPPuaP0V_V4