Laboratory
Gemological Institute of America (GIA)
Carlsbad, United States
Diamonds, lab-grown diamonds, coloured stones, pearls
The Gemological Institute of America (GIA), a non-profit founded in 1931, created the 4Cs and the International Diamond Grading System used across the trade. Its laboratories are headquartered in Carlsbad, California, with labs in many trading centres.
What it does
Diamond grading reports and dossiers, laboratory-grown diamond reports, coloured stone identification and origin reports, pearl reports, and research published in Gems & Gemology. Laser inscriptions link stones to their reports.
Laboratories include New York, Mumbai, Surat, Bangkok, Hong Kong, Tokyo, Ramat Gan, Antwerp, Gaborone and Dubai.
Using any laboratory
- Ask what the report will state (identity, treatment, origin, grade) and how long it takes; turnaround and fees change.
- Check a report online with the laboratory's own report-check service, and match the stone to the report.
- Reports from different laboratories can differ, especially on colour grades, treatment and origin. A report is an opinion based on the tests made, not a valuation.
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