GIA's Laboratory-Grown Diamond Quality Assessment rates a lab-grown diamond Premium or Standard. It replaced GIA's D-to-Z lab-grown reports on 1 October 2025.
In more detail
It covers loose, colorless to near-colorless lab-grown diamonds of 0.15 ct or more. GIA gave its reason: most lab-grown diamonds fall in a very narrow range of color and clarity. Premium needs D color, VVS clarity or higher, Excellent polish and symmetry, and Excellent cut for a round. A stone below the Standard minimums gets no assessment.
On a grading report
The assessment states Premium or Standard, not a color or clarity grade. GIA inscribes "Laboratory-Grown" and the assessment number on the girdle.
Related terms
- Laboratory-grown diamond: A laboratory-grown diamond is a diamond that people grow with machines, by HPHT or CVD. It has essentially the same composition, crystal structure and properties as a natural diamond.
- Laboratory-Grown Diamond Report: The Laboratory-Grown Diamond Report was GIA's digital-only report for laboratory-grown diamonds, from October 2020 to September 2025. It gave color and clarity grades and stated the growth method, CVD or HPHT.
- Diamond grading report: A diamond grading report is an independent lab's record of what a stone is and how it grades. It is true for the day the lab examined the stone.
- Inscription: An inscription is text that a laser writes on the girdle of a stone, too small to see without magnification. Most often it is the report number.