Lab Grown Grading: The Big Divide

Should lab growns be graded like natural diamonds?

It's a simple enough question, but the answer is not so straightforward, as evidenced by three announcements in recent weeks by three labs - all taking different positions.

In short, GIA says no. The 4Cs are no longer relevant for lab growns and it will grade them simply as standard or premium.

IGI says yes. The 4CS are extremely relevant for lab growns, and it will carry on treating them just like natural stones.

And HRD says no, and emphatically so. It is taking such a firm stance in favor of natural diamonds that it will no longer routinely grade lab growns.

Before we delve a little deeper into their approaches, let's zoom out and think for a moment about how we adapt to innovation.

We frame the new thing in terms of the old. So the first cars were "horseless carriages". Photography was "mechanical painting". TV was "radio with pictures".
 
As time goes on the differences become the new and the old more pronounced and the new thing becomes more established.

But it's a process, and there will be false starts, misunderstandings and changes of heart along the way.

So it is with lab grown diamonds. Grading labs have been forced to decide whether they treat them just like natural stones, unlike natural stones, or somewhere in between.

GIA, the market leader, has gone full circle - no, yes and no again when it comes to applying its 4Cs grading to lab growns.

It started issuing what it called "Synthetic Diamond Reports" in 2006, taking a very cautious stance, clearly stating the diamond's man-made nature multiple times and deliberately avoiding the  4Cs marketing terminology.

Color and clarity were described in ranges - "Near-Colorless (G-J)" or "VS to SI" - rather than individual grades, and lab grown reports had a different format and color scheme.

Then in 2019 it softened its approach, styling its reports as being for "laboratory-grown" rather than "synthetic" diamonds and adopting a format much closer to natural diamond grading.

It started using the 4Cs terminology that it had so pointedly avoided in the past, although it still certified ranges rather than individual grades.

That was how things stood until last month, when it announced a move in the opposite direction, to a position more extreme than it originally took in 2007.

No more color or clarity information at all, just a binary choice between standard and premium.

"More than 95 per cent of laboratory-grown diamonds entering the market fall into a very narrow range of color and clarity," said Tom Moses, GIA executive vice president and chief laboratory and research officer.

"Because of that, it is no longer relevant for GIA to describe man-made diamonds using the nomenclature created for the continuum of color and clarity of natural diamonds."

IGI has stuck to its guns, issuing 4Cs grading certificates for lab growns from the get-go in 2005 and never wavering from that position. Lab growns now represent the bulk of its revenue - 54 per cent according to its Q1 2025 financial results.

In a statement this week, reaffirming that position, it said: "Recognizing their identical properties to natural diamonds, IGI applied the existing 4Cs to prevent industry and consumer confusion, mirroring the approach taken in the cultured pearl market.

"This affirmation comes as many in the industry grapple with the unprecedented shift by others to a different, diluted scale for lab grown diamonds sent to their locations."

HRD started grading lab growns in 2013, limiting itself to five color ranges, from "colorless" to "light" and three clarities - FI (Free of Inclusions), SI (Slightly Included) and I (Included).

From 2019, it started grading lab growns just like natural diamonds, using the same scales of 13 colors and 10 clarities to provide "the most accurate grading report possible, offering a true description of the diamond".

But last month it announced an abrupt U-turn, saying it would no longer be grading lab growns (with limited exceptions) in order to create a "clear distinction between natural and synthetic diamonds".

Karen Rentmeesters, CEO of AWDC, the lab's parent company, said: "By becoming the first diamond lab in the world to take an explicit and exclusive stance in favour of natural diamonds, HRD Antwerp is sending a strong signal."

GIA and HRD don't say exactly what proportion of their business is lab grown, but it's small. IGI makes no bones about it. Lab growns are the majority of their business.

So we shouldn't be surprised that IGI takes the position it does, or that GIA and HRD take the positions they do.

They're simply mirroring the divide between two increasingly different and distinct products in the wider industry.

Have a fabulous weekend.