GIA and IGI are two of the most widely recognised diamond grading laboratories in the world, and they are the two laboratories behind the reports on our diamonds. Both issue reports describing a diamond’s characteristics, but their report types differ, and GIA changed how it describes laboratory-grown diamonds in 2025. Here is what each covers and whether the difference matters when you commission an engagement ring.
TL;DR: GIA (Gemological Institute of America) was founded in 1931 and created the 4Cs and the International Diamond Grading System used for natural diamonds. IGI (International Gemological Institute) was founded in Antwerp in 1975 and grades natural and laboratory-grown diamonds in laboratories around the world. Since October 2025, GIA describes colourless to near-colourless lab-grown diamonds as “Premium” or “Standard” rather than giving letter colour and clarity grades. At À Vie Diamonds, our diamonds come with GIA or IGI reports.
What a Grading Report Is
A diamond grading report (often called a certificate) is a document issued by an independent gemmological laboratory that records the characteristics of a specific diamond. It is not a valuation and does not state what the diamond is worth. For a natural diamond, a full GIA Diamond Grading Report covers the 4Cs (colour, clarity, cut and carat weight), polish, symmetry and fluorescence, with a plotted diagram of clarity characteristics and a proportions diagram. Some shorter report types, such as GIA’s Diamond Dossier, omit the plot. GIA issues a cut grade only for standard round brilliants. See our full guide to reading a GIA certificate for a section-by-section breakdown.
The report is linked to the stone by its recorded characteristics and, where present, a laser inscription of the report number on the girdle, which can be checked under magnification. Both laboratories let you check a report number online. If a stone is recut or damaged, the original report no longer describes it accurately.
GIA: The Gemological Institute of America
GIA was founded in 1931 and is an independent nonprofit organisation based in California. It created the 4Cs and, in 1953, the GIA International Diamond Grading System, including the D to Z colour scale and the Flawless to I3 clarity scale.
For natural diamonds, GIA reports are a widely used reference point. GIA has also issued reports for laboratory-grown diamonds since 2007. From 1 October 2025, its Laboratory-Grown Diamond Quality Assessment classifies colourless to near-colourless lab-grown diamonds as “Premium” or “Standard” based on colour, clarity, polish, symmetry and, for rounds, cut, instead of using the colour and clarity grades it created for natural diamonds. Stones below the Standard criteria do not receive an assessment, and the girdle is inscribed “Laboratory-Grown” with the assessment number. GIA says existing lab-grown reports remain valid.
IGI: The International Gemological Institute
IGI was founded in Antwerp in 1975 and now operates laboratories around the world grading natural diamonds, laboratory-grown diamonds, coloured gemstones and finished jewellery. Its laboratories hold ISO accreditation for both natural and lab-grown diamond grading. IGI is a familiar name on lab-grown diamond reports, which typically show colour and clarity grades on the same scales used for natural diamonds. IGI states that lab-grown diamonds it reports on have the prefix “LG” laser inscribed on the girdle ahead of the report number.
IGI grades cut for round brilliants and, since 2022, offers an optional cut grade for fancy shapes. All IGI reports note polish and symmetry.
Does the Laboratory Matter?
For a natural diamond, a GIA report is a familiar and widely accepted reference, and IGI also grades natural diamonds. For a lab-grown diamond, an IGI report typically shows colour and clarity grades, while a recent GIA assessment gives a Premium or Standard classification, so the two read quite differently.
Grading involves expert judgement, and two laboratories will not always describe the same stone identically. That is why comparing stones on paper across different laboratories is less reliable than comparing stones graded by the same laboratory, and why seeing the stone itself matters.
For a buyer commissioning a bespoke ring, the report is the starting point rather than the whole answer. Viewing the stone on video, checking how it handles light and working with a maker who sources carefully all matter alongside the name at the top of the report.
Other Laboratories
Other laboratories also issue diamond reports, and standards and familiarity vary. If you are offered a stone with a report from a laboratory you do not recognise, it is reasonable to ask why that laboratory was used and how its grading compares. Our diamonds come with GIA or IGI reports.
At À Vie Diamonds
We source every gem for our commissions, natural or lab-grown, and our diamonds come with GIA or IGI reports. Ask to see photography and, where available, video of shortlisted stones before you choose, and check the report number on the laboratory’s website. Read our story to learn more about us. See our natural diamonds guide, our lab-grown diamonds guide and our clarity guide for more on how grading affects stone selection. Get in touch to discuss a commission.
Related Reading
- How to Read a GIA Diamond Certificate
- Diamond Treatments Explained: what the report discloses about treated stones
- What Is an Eye-Clean Diamond?
Frequently Asked Questions
Is GIA better than IGI? Neither is simply better for every purpose. GIA created the grading system used for natural diamonds and its reports are a widely used reference for natural stones. IGI is a major international laboratory grading both natural and lab-grown diamonds. For lab-grown stones, the two now present quality differently, so it helps to understand which report you are reading.
Are IGI reports reliable? IGI is a major, internationally recognised laboratory with ISO accredited natural and lab-grown diamond grading. As with any report, it is best read alongside photographs or video of the stone.
Why does a GIA lab-grown report say Premium or Standard? Since 1 October 2025, GIA classifies colourless to near-colourless lab-grown diamonds as Premium or Standard rather than giving letter colour and clarity grades. Earlier GIA lab-grown reports remain valid.
Can I request a specific laboratory for my stone? Yes. If you prefer GIA or IGI, tell us at the start and we will take that into account when sourcing.
What does a diamond report tell me? For a natural diamond, the 4Cs (with a cut grade for standard round brilliants), plus proportions, polish, symmetry and fluorescence, and on full reports a plot of clarity characteristics. It does not state a monetary value and is not a valuation for insurance, although insurers may ask to see it.
Last reviewed: November 2026 · À Vie Diamonds