If you're interested in purchasing a lab-grown diamond certified by GIA, it's more important than ever to be aware of the updates being made by GIA to their grading system.
The certification date of your diamond determines both how it was graded and whether you'll receive a digital or physical report.
Since introducing lab-grown diamond reports in 2007, GIA's grading approach has evolved significantly. The system reached its most detailed form between August 2020 and September 2025, when lab-grown diamonds were graded using the same comprehensive grading as natural diamonds.
However, October 2025 marked a dramatic shift in GIA's methodology.
The Big Change
On 1 October 2025, the Gemmological Institute of America (GIA) fundamentally transformed how it grades lab-grown diamonds.
Gone are the specific color and clarity grades you're familiar with. Learn more about The 4Cs: Natural and Lab-Grown Diamonds Explained .
In their place? Just two broad categories: "Premium" and "Standard." If your lab-grown diamond doesn't meet even the minimum Standard criteria, or if your diamond is less than 0.15 carats, GIA won't issue a report at all.
| Minimum Criteria | Premium | Standard |
|---|---|---|
|
Colour |
"D" |
"J" or better |
|
Clarity |
"VVS" or better |
"VS" or better |
|
Polish |
"Excellent" |
"Very Good" or better |
|
Symmetry |
"Excellent" |
"Very Good" or better (or "Good" or better, for fancy shapes) |
|
Cut (Round Brilliant) |
"Excellent" |
"Very Good" or better |
Other changes include the removal of clarity characteristics and inclusion plotting diagrams, and the return of physical, printed certificates.
Whilst these new certifications will certainly be easier and faster to understand, it also marks a loss of transparency.
For example:
- A "Premium" stone could refer to clarity of either VVS1, VVS2, IF or FL. In addition, with no clarity characteristics or inclusion plotting diagrams available, you won't be able to see whether or what type of inclusions exist in your diamond.
- A "Standard" stone could have an E colour, but have other premium-like features, such as IF Clarity, Excellent Polish, Symmetry and Cut.
Grading System Comparison
To help simplify your purchase, we've created a comparison table for the different periods of GIA lab-grown diamond grading systems.
| GIA Grading Systems | Stage 1 | Stage 2 | Stage 3 (Report) | Stage 3 (Dossier) | Stage 4 |
|---|---|---|---|---|---|
|
Time Period |
Jan 2007 – Jun 2019 |
Jul 2019 – Aug 2020 |
Aug 2020 - Sep 2025 |
Aug 2020 - Sep 2025 |
Oct 2025 onwards |
|
Duration |
12 Years |
1 Year |
5 Years |
5 Years |
Ongoing |
|
Report Name |
Synthetic Diamond Grading Report |
Laboratory-Grown Diamond Report (Transition) |
Laboratory-Grown Diamond Report |
Laboratory-Grown Diamond - Dossier During this period, two types of reports were available. The "Dossier" is a summarised certificate with reduced information. |
Laboratory-Grown Diamond Report Quality Assessment |
| Colour, Clarity and Cut | |||||
|
Colour |
Use of descriptive terms including "Colourless", "Near Colourless", "Faint", "Very Light" and "Light". Different terminology to natural diamonds used. |
Use of descriptive terms including "Colourless", "Near Colourless", "Faint", "Very Light" and "Light". Reference provided e.g. "Colourless" refers to D, E or F. Different terminology to natural diamonds used. |
Specific letter grades used from "D" to "Z". Same grades as natural diamonds. |
Specific letter grades used from "D" to "Z". Same grades as natural diamonds. |
Classification of "Premium" ("D") and "Standard" ("J" or better) only. Different grading terminology to natural diamonds used. |
|
Clarity |
Use of descriptive terms, including "Flawless", "Internally Flawless", "Very Very Slightly Included", "Very Slightly Included", "Slightly Included", and "Included". Different terminology to natural diamonds used. |
Use of descriptive terms, including "Flawless", "Internally Flawless", "Very Very Slightly Included", "Very Slightly Included", "Slightly Included", and "Included". Reference provided e.g. "Very Very Slightly Included" refers to VVS1 or VVS2. Different terminology to natural diamonds used. |
Specific letter grades used from "FL" to "I3". Same grades as natural diamonds. |
Specific letter grades used from "FL" to "I3". Same grades as natural diamonds. |
Classification of "Premium" ("VVS" or better) and "Standard" ("VS" or better) only. Different grading terminology to natural diamonds used. |
|
Cut |
Specific term grades used from "Excellent" to "Poor". Same grades as natural diamonds. |
Specific term grades used from "Excellent" to "Poor". Same grades as natural diamonds. |
Specific term grades used from "Excellent" to "Poor". Same grades as natural diamonds. |
Specific term grades used from "Excellent" to "Poor". Same grades as natural diamonds. |
Classification of "Premium" ("Excellent") and "Standard" ("Very Good" or better) only. Different grading terminology to natural diamonds used. |
| Additional Information | |||||
|
Clarity Characteristics |
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|
Inclusion Plotting Diagram |
|
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|
Proportions Diagram |
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|
Growth Method |
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Post-Growth Treatments |
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|
Report Format |
Physical, printed report |
Physical, printed report |
Digital only. |
Digital only. |
Physical, printed report. |
|
Laser Inscription |
GIA Report Number and a statement that the stone is laboratory-grown. |
GIA Report Number and a statement that the stone is laboratory-grown. |
"Laboratory-Grown" followed by GIA Report Number |
"Laboratory-Grown" followed by GIA Report Number |
"Laboratory-Grown" followed by GIA Quality Assessment Number |
Yes, provided with description.
No, not provided.What Does This Mean For You?
The lab-grown diamond industry is evolving rapidly, and grading standards are evolving with it.
GIA's October 2025 update represents a major philosophical shift - one that prioritises simplification and differentiation over detailed technical grading.
For consumers, this distinction directly impacts the choice between GIA and IGI certification.
Whilst neither is inherently "better", they serve different needs. The key is understanding what you're getting (or not getting) with each option and choosing the certification that aligns with your priorities. To help with this choice, view our GIA vs IGI decision tree at GIA vs IGI: Which Certifier Should You Choose For My Gemstone? .
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