The move was first announced in June, though without a timeline. In a statement issued on 26 August, GIA outlined the criteria for each category. Diamonds that fail to meet the minimum requirements for “Standard” will not receive a GIA assessment.

Premium lab-grown diamonds must meet:

• Clarity: Very, Very Slightly Included (VVS) and higher

• Color: D

• Polish and Symmetry: Excellent

• Cut: Excellent (round brilliant only)

Standard lab-grown diamonds must meet:

• Clarity: Very Slightly Included (VS)

• Color: E to J

• Polish: Very Good

• Symmetry: Very Good (or Good for fancy shapes)

• Cut: Very Good (round brilliant only)

GIA will charge $15 per carat, with a minimum fee of $15. Diamonds falling below the Standard threshold will still incur a $15 evaluation fee but will not be assigned a grade.

“Using descriptive terms for the quality of laboratory-grown diamonds is appropriate as most fall into a very narrow range of color and clarity,” said Pritesh Patel, GIA President and CEO. “Because of that, GIA will no longer use the nomenclature created for natural diamonds to describe what is a manufactured product.”

The announcement highlights a growing divide in the industry. Rival laboratory IGI (International Gemological Institute) has stated it will continue with traditional 4Cs grading for lab-grown diamonds, arguing that consistency is vital to avoid industry and consumer confusion.