How do I buy loose lab-grown diamonds for custom settings?

ZKZ Editorial TeamMain answer · Product & gemmology desk

Buy against a written specification and a laboratory report, check each stone on arrival and keep the records. GIA states that its laboratory-grown reports are for loose stones of 0.15 carats or more and that the girdle is inscribed with the report number, so reported stones can be matched to their paper trail.

What we verified

Fact GIA says its Laboratory-Grown Diamond Quality Assessment is for loose, colourless to near-colourless stones of 0.15 carats or more, and the girdle is laser inscribed with the term Laboratory-Grown and its number.

Fact GIA says its laboratory-grown reports are digital only, and that if a report can be found on its Report Check, it is authentic.

Fact IGI lets you verify a report by report number, SKU lookup or QR code.

Fact The FTC Jewelry Guides (16 CFR 23.25) say a laboratory-grown stone should be described with laboratory-grown wording with equal conspicuousness to words such as gem, gemstone or stone.

A sourcing checklist

1. Write the spec: shape, weight range, colour, clarity, cut or finish, report laboratory and tolerance.
2. Ask for the report number before you pay and check it on the laboratory site.
3. Inspect on arrival: weight, size, inscription and a loupe check against the report.
4. Keep stones sealed and labelled with the order and report numbers.
5. Agree return terms for stones that do not match.

Our advice Start with a small order from a new supplier before you commit to larger quantities.

It depends Reports differ between laboratories, and a supplier may offer several laboratories.

Planning the setting around the stone

Our advice Design the setting around a tolerance, not a single number. Loose stones of the same nominal size vary slightly, so ask the setter what range of diameter and depth each seat can accept. Keep a few spare stones per order for breakage during setting, and agree who bears that cost. Decide early whether the settings are made first and the stones set later, or stones are bought for each design, because that decides how much stock you hold.

Our advice Record the report number against the finished piece, so a customer question months later can be answered quickly.

Uncertain We did not verify supplier reliability checks, price levels or typical lead times.

Related reading: Can a Lab-Grown Diamond Pass a Diamond Tester? · Custom Lab Grown Diamond Jewelry: A Step-by-Step Guide

Sources

• GIA, Laboratory-grown diamond services
• GIA, How can I be sure my laboratory-grown diamond report is authentic?
• IGI, Verify your report
• 16 CFR 23.25, FTC Jewelry Guides: misuse of "ruby", "sapphire", "emerald", "birthstone", "gem" and similar words

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