The National Gem Lab · Surat

Know exactly what you hold.

Independent testing of diamonds, gemstones and jewellery, with every report verifiable online.

Submit a stone About the lab

The National Gem Lab Gemological Testing Laboratories Of India

10+Years in gemology

24/7Online report verification

3Offices: Surat, Dubai, Kamloops

100%Private and independent

Laboratory reports

A report for every stone, and every setting.

Each report carries a unique number, a photograph and a QR code that links back to our records, so anyone can confirm it is genuine.

Diamond

Shape, carat weight, color, clarity and cut for loose diamonds.

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Jewelry

Finished pieces assessed as set, with metal, weight and stone details.

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Colored stone

Species, variety and detectable treatments for colored gemstones.

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Laboratory grown

Clear disclosure and grading for laboratory grown diamonds.

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Hearts & Arrows

Optical symmetry analysis for precisely cut round brilliants.

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Laserscribe

Your report number, inscribed microscopically on the girdle.

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Verification

Check a report in three steps.

Buying a stone with a GTLI report? Take a minute to confirm the details match our records before you pay.

Find the number

Look for the Certi No or Report ID on the card, or scan the QR code with your phone camera.

Enter it here

Type it into the verify box on any page. Slashes and hyphens are fine, spaces are ignored.

Compare the card

Weight, colour, photo and comments should match the card in your hand exactly.

10+years of
gemology

Who we are

A private gem laboratory in Surat.

GTLI is a purely private laboratory, not related to any government lab. Our purpose is simple: protect buyers and sellers with accurate diamond and gemstone reports. Every stone is examined with up-to-date instruments and checked by experienced gemologists before a report is issued.