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    Diamond grading reports

    GIA, IGI, AGS, HRD and AnchorCert reports — how to read and verify them.

    Typical UK second-hand price

    A trusted report can add 10–30% to resale value

    Main laboratories

    • GIA — the global benchmark, strictest colour and clarity grading.
    • IGI — very common for lab-grown and retail jewellery.
    • AGS — strong on cut grading.
    • AnchorCert (Birmingham Assay Office) — respected UK lab.
    • HRD — Antwerp lab, widely used in Europe.

    Valuations are not grading reports

    An insurance valuation states a replacement retail price, usually far above second-hand value. It is not an independent grading report.

    Before you buy

    • Verify the report number on the lab's website.
    • Match carat weight and measurements to the stone.
    • Have any high-value piece checked by an independent valuer or jeweller before paying. JewelleryTrader does not authenticate items.

    Frequently asked questions

    Can a report be faked?

    Yes. Always look the number up on the lab's own site and match the girdle inscription.

    More diamonds guides

    The 4Cs explainedDiamond shapes and cutsLab-grown vs natural diamonds

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