1 - IDENTIFICATION
In order for the gem to be
properly identified, O.P.E.C. have either
the certificates laboratories of the «
Gemological Institute of America - G.I.A. »
or the « French Gemological Laboratory –
Public Service For the Control Of Diamonds,
Natural Pearls and Precious Stones » or the
« Department of Pearl-culture (Papeete) ».
An identification examination
is delivered and the O.P.E.C. pearls are
offered for sale, each pearl being sold with
its gemological certificate.
Widespread sale of tinted
pearls and (remarkable) imitations of the
Tahitian Black Pearl, have prompted the need
for protection through thorough laboratory
3 - QUALITY
cultured pearl is the result of depositing calcium carbonate (93%) on a
nucleus originating from a fresh water bivalve shell.
Thickness and the quality of the pearl layers are essential to the
quality of the luster and life-span of the pearl.
In order to be able to access how thick the Mother of Pearl (M.O.P.) is
around the nucleus, O.P.E.C. x-rays every single pearl destined to be
X-ray reading makes it possible to accurately assess the thickness of
the M.O.P. and is also an essential factor in pearl appraisal.
Everyone in the Trade agrees on saying that the thickness of the M.O.P.
is a critical element in the value of a cultured pearl and recommends
that no compromise should be made in this respect.
People in the trade also recommend that all those not adhering to the
above should not be considered as worthy of the trade. (refer to «The
Pearl Buying Guide» par Renée Newman GG, International Jewelry
The Polynesian government has taken necessary measures to control the
thickness of the mother of pearl on all the exported pearls. Therefore,
it has limited the mother of pearl minimum size to 0,8 mm starting July
2 - CLASSIFICATION
Once the identification has been performed by
the laboratory and the reading of the x-ray photo has been
completed, the Tahitian Black Pearl is classified according
to its characteristics : shape, size, luster and surface
quality. Perfect pearls are thus classified as follows : "A"
then "B", "C", "D".