GIA Shakes Up Lab-Grown Diamond Grading Standards: What This Means for Buyers of Diamonds and Diamond Jewellery

The Gemmological Institute of America (‘GIA’) is changing how it grades lab-grown diamonds. Discover what this seismic shift in the diamond industry means for consumers, quality standards, and the future of luxury diamond jewellery.

The Diamond World Just Changed – Here’s Why it Matters

On 2 June 2025, GIA shook the world of diamonds and luxury jewellery with their surprise announcement – they are redefining how laboratory-grown diamonds are graded and described. For the millions of consumers who are turning to more sustainable, ethical, affordable and higher quality lab-grown diamonds, this is news worth knowing!

What Exactly Has Changed? Understanding the GIA’s New Grading System

The End of the “4 Cs” – At Least for Lab-Grown Diamonds

GIA was the organisation which first established and then adopted “the 4 Cs” grading structure for diamonds – these being Cut, Colour, Clarity, and Carat. This became the global standard for describing the quality of different diamonds – and, crucially, this is set to remain for mined diamonds. However, GIA has announced that they will no longer apply these traditional categories to the grading of lab-grown diamonds.

New Descriptive Terminology

GIA is introducing just two categories for lab-grown diamonds – “Premium” and “Standard.” Whilst these categories will be defined according to a combination of cut, clarity, and finish, it remains to be seen where the lines between these categories will be drawn.

This will be no less than a whole new framework for grading lab-grown diamonds. Moreover, as the traditional 4 Cs will be retained for mined diamonds, GIA’s new grading system will further provide a clear distinction being drawn between lab-grown and mined diamonds.

Why the Change? A Step Towards Transparency or Division?

GIA’s stated reason for the revised descriptive system is provided by Tom Moses, Executive Vice-President and Chief Laboratory and Research Officer:

“More than 95% of laboratory-grown diamonds entering the market fall into a very narrow range of colour and clarity. Because of that, it is no longer relevant for GIA to describe man-made diamonds using the nomenclature created for the continuum of colour and clarity of natural diamonds.”

For some, a distinct grading system for lab-grown diamonds is a move towards greater transparency for the diamond and jewellery industries. Not only will the distinct grading systems enable consumers to distinguish easily between lab-grown and mined diamonds, but it will greatly simplify the grading categories for lab-grown diamonds, further empowering consumers to distinguish between higher- and lower-quality stones.

Conversely, early critics of GIA’s announcement accuse the move as being targeted towards dividing the diamond industry. Mined and lab-grown diamonds are exactly the same material, being physically, chemically, and optically identical – just created differently. The mined diamond industry is therefore understandably threatened by the potential for lab-grown diamonds to become the dominant product, with their generally higher quality and significantly more affordable price tag. The adoption of distinct grading systems may therefore be interpreted as an attempt to distinguish lab-grown diamonds as a less desirable product.

What This Means for You, the Buyer

How Your Evaluate Quality Will Shift

Buyers will need to understand the new descriptive language around lab-grown diamonds, and will likely want to be able to draw comparisons between the Premium and Standard categories and the 4 Cs. That being said, the technology behind lab-grown diamonds has greatly increased the quality of this product over time, such that the adoption of only two grading categories is bound to be of greatest benefit to consumers who are less familiar with traditional grading methods.

Certification Still Matters – But It’s Evolving

GIA certification carries significant weight in the diamond industry, and it is entirely possible that the organisation will trigger a similar move across the grading industry. In the first years, however, GIA’s adoption of such a radically different grading system will create some inconsistency in grading between GIA and other grading labs such as IGI and GCAL.

A Turning Point for Lab-Grown Diamonds

At Hinch & Liu, our in-house DGA-qualified diamond grader thinks that GIA’s announcement is particularly exciting, because it potentially signals a maturation of the lab-grown diamond as a category of jewellery product. A distinct grading system may usher in greater innovation within the lab-grown industry, bring more transparency to the market, and empower consumer with greater education about their product.

This also represents an opportunity for lab-grown diamond certification to adopt categories that are more significant to this particular industry, such as certifying diamonds for their environmental and sustainability credentials.

As for consumers of lab-grown diamond jewellery, continue to look out for credible diamond jewellers who should always offer certification from a leading laboratory such as GIA and IGI. Don’t be afraid to ask questions about the certification, origin, and quality of particular diamonds, and pay attention to the brand trust and reputation of your jeweller.

Lab-Grown Diamond Jewellery – Because Diamonds Shouldn’t Cost the Earth

As the diamond world evolves, one thing is clear – lab-grown brilliance is here to stay. If you’re looking for timeless, ethically-crafted, luxury jewellery that transcends labels, explore the Hinch & Liu collection—where craftsmanship meets conscious elegance.