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BGI
Certificates
The BGI offers a range of certificates to
suit every need from loose stones to mounted Jewellery Reports, even rough
or carved gemstones.
The BGI supports international conventions for
standard diamond grading by using Official Master Stones grawded by senior graders at Lazare
Kaplan of New York
and the Gemmological Institute of America. This confirms the authority of
the diamond grades set by BGI Laboratory, ensuring that the highest
standards are the same all over the world.
Our experts use modern gemmological testing
equipment including the latest De Beers Photo-Spectrometer which checks
nitrogen levels in the atomic structure of diamonds. We also use microscopy
and spectroscopy which analyse the light inside the gemstone.
Each gemstone is rigorously checked, tested
and weighed according to the measuring conventions of the official World
Federation of Diamond Bourses [WFDB].
Each certificate shows:
1. Full Certificate
(Ask for Ref: 801): showing the complete range of primary qualities of
a diamond, including a diagram of 10x visible flaws, external inclusions or
marks, and the diamond's 'proportions' (see section); with BGI seal and
hologram.
2. Mid Certificate
(Ask for Ref: 601): Showing colour, clarity, dimensions, fluorescence,
but without a diagram as above; BGI seal.
3. Card Certificate: Literally a neat
'credit card sized' certificate detailing the diamond's main features as in
the '601' above, and a colour picture of the shape of the diamond.
4. Jewellery Report: Shows a colour
picture of the item (or main section) usually with a 2 span colour grade,
and 2 purity grades (clarity), to take some account of what may remain
obscured by the setting. This can be used for most types of diamond
jewellery, while more important coloured gems may need to be unset if
diagnosis is more complex.
5. Coloured Stone
Report: For non-diamond coloured gemstones, such as ruby, sapphire
and emerald, alexandrite, topaz etc.
6. Coloured Diamond
Report: using more advanced techniques to test the natural origin
of the diamond, and give an opinion on the exact colour based on the
grader's trade experience.
7. Gem Origin
Report: usually used for coloured gems of all kinds where the
country of origin can affect the value, this series of tests provides the
evidence for the BGI opinion on that 'origin', which often forms a separate
and useful addition to the Report on the gem in '5' above.
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