What does a girdle laser inscription tell me and how do I read it?

925 sterling silver jewellery, set with lab grown diamonds and made in our own Shenzhen workshop.

Posted on October 24, 2026by test111

Talk · Compliance & disclosure

QThe questionEditorial scenario written by the ZKZ team. Not a customer post.

A buyer receives a lab-grown diamond ring with a report. Under a loupe the thin edge of the stone shows tiny engraved characters. They want to know what the inscription means, whether it proves anything and how to check it.

ZKZ Editorial TeamMain answer · Product & gemmology desk

A girdle inscription is a tiny laser-engraved line on the thin edge of the stone. It normally carries the stone's report number and, depending on the laboratory, a sign that the stone is lab-grown. It lets you match the stone to its report, but it only proves what the report proves, so you still have to look the number up with the laboratory.

What GIA inscribes

Fact GIA states that stones submitted for its laboratory-grown diamond services have the girdle laser-inscribed with the term "Laboratory-Grown" and the GIA report or quality assessment number. If a stone already carries an acceptable laboratory-grown inscription, GIA inscribes only the new number.

Fact GIA says its report numbers can be verified through GIA's report check on its website.

What IGI inscribes

Fact IGI offers a verification page where you enter the report number to see the report details.

Uncertain Trade press has reported that IGI inscribes its lab-grown diamonds with the letters "LG" followed by the report number, rather than the words "LAB GROWN". We could not confirm this on IGI's own pages, so treat the exact format as something to check against the report itself.

How to check the stone

Find the number on the report and the number on the stone. A 10x loupe or a jeweller's microscope is usually needed because the characters are very small.
Enter the number on the laboratory's own verification page, not on a link supplied by the seller.
Compare the report details (shape, weight, measurements, grades) with your stone and its listing. Weight and measurements should match.
Ask the jeweller to confirm the inscription under magnification if you cannot read it.

What it does not prove

Our advice An inscription is not a quality guarantee. It shows which report belongs to the stone; whether the stone is a good purchase depends on what the report says and on how the seller describes it. A missing or unreadable inscription is not proof of a problem, but it makes it harder to verify, so ask the seller how the stone is identified.

Our advice Inscribing can be done on a stone that was already set, but the inscription may be hidden under a prong or bezel. Ask the seller to confirm that the stone in your ring is the stone in the report.

It depends Whether the laboratory inscribes a stone, and with what wording, depends on the laboratory, the date of the report and the service ordered. Older reports may have different inscription styles.

Sources

Fact = stated by the cited source. Our advice = editorial recommendation. Uncertain / it depends = limits of what can be said in general.

Other perspectives from the ZKZ team

COZKZ Editorial TeamDisclosure & compliance perspective

An origin word on the stone or the report is useful, but the listing still has to say "laboratory-grown" in plain words. The inscription supports the disclosure; it does not replace it.

SEZKZ Editorial TeamSelection perspective

Do the check once, in the first week, while it is easy to return the piece. Keep a photo of the report and the inscribed number with your order records.

CSZKZ Editorial TeamCare & maintenance perspective

Tell the jeweller about the inscription before any repair. Prongs and bezels can cover it, and a reset that hides the number makes future checks harder.

Have a different question? Ask our team, or browse more answers in Talk.

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