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If you’re shopping for a lab-grown diamond—or you already own one with a GIA report—GIA’s August 2025 announcement is a big deal. Starting October 1, 2025, the Gemological Institute of America (GIA) is changing how it evaluates D-to-Z laboratory-grown diamonds, replacing its prior approach with a new GIA Laboratory-Grown Diamond Quality Assessment that uses “Premium” and “Standard” classifications (and may issue no assessment at all if minimum criteria aren’t met).
Source: GIA press release (Aug 26, 2025)
Key Takeaway:
This change is designed to differentiate lab-grown diamonds from natural diamonds in how GIA communicates quality, rather than making lab-grown reports look more like natural diamond grading reports.
What GIA Announced (And When It Starts)
GIA stated it will launch revised evaluation services for D-to-Z laboratory-grown diamonds on October 1, 2025, and that its prior lab-grown services for D-to-Z laboratory-grown diamonds would be available through September 30, 2025.
Instead of issuing a traditional-style grading report using the nomenclature created for natural diamonds, GIA’s updated lab-grown service provides an overall quality assessment with descriptive classifications: Premium or Standard.
Premium vs. Standard: The Minimum Criteria (Straight From GIA)
GIA explained that lab-grown diamonds will be described as “Premium” or “Standard” based on an overall assessment of clarity, color, and cut. Any diamond that does not meet minimum criteria for “Standard” will not receive a GIA assessment. See our article on the 4C’s – Diamond pricing factors.
Premium (all criteria must be met)
- Clarity: Very, Very Slightly Included and higher
- Color: D
- Polish & Symmetry: Excellent
- Cut Grade: Excellent (round brilliant cut diamonds only)
Standard (meets minimum criteria; may meet some “Premium” criteria too)
- Clarity: Very Slightly Included
- Color: E-to-J
- Polish: Very Good
- Symmetry: Very Good (or Good for fancy shapes)
- Cut Grade: Very Good (round brilliant cut diamonds only)
For context, GIA’s natural diamond color scale is commonly referenced as D-to-Z (with D being “colorless” and increasing letters showing more color). Source: GIA – Diamond Color (D-to-Z)
Fees, Submission Minimums, and Laser Inscription
GIA also published operational details that matter if you’re submitting a stone or interpreting what retailers are listing:
- Fee: US$15 per carat (minimum fee US$15)
- If the stone doesn’t meet minimum criteria: US$5 evaluation fee
- Minimum size for submission: 0.15 carats
- Laser inscription: “Laboratory-Grown” + the GIA quality assessment number
- Output: a printed document with assessment results returned with each lab-grown diamond
If you want a second official reference for the updated service structure and effective date, GIA’s laboratory fee schedule documents also reflect the new lab-grown quality assessment framework effective October 1, 2025.
What This Means If You’re Shopping (Or Comparing Listings Online)
Practically, this change can make comparisons feel different depending on what inventory you’re looking at:
- New GIA lab-grown documents may emphasize “Premium” vs. “Standard” instead of presenting the same natural-diamond-style grading language you’re used to.
- Older GIA lab-grown reports (issued before October 1, 2025) may be formatted differently and may include different types of detail depending on what service was used at the time.
- Some stones may receive no assessment if they don’t meet the minimum criteria for “Standard.”
The most reliable way to compare lab-grown diamonds—especially during this transition—is to look beyond the headline label and focus on objective listing details (carat, measurements, proportions, and how the market is pricing similar stones across retailers).
How Diamond Watcher Helps
When report formats change, it’s easy for pricing to get noisy across retailers. That’s where DiamondWatcher.com comes in: it helps you compare diamonds across sites so you can see how stones with similar specs are actually priced in the real market.
As GIA’s updated lab-grown services roll out, using side-by-side comparisons across retailers can help you stay grounded in value—especially when listings mix older and newer GIA documentation styles.
Final Thoughts
GIA’s August 2025 announcement is a clear pivot: starting October 1, 2025, GIA’s lab-grown evaluation for D-to-Z laboratory-grown diamonds moves to a quality assessment framework that classifies qualifying stones as Premium or Standard, with minimum criteria and the possibility of receiving no assessment if those minimums aren’t met.
If you’re shopping now, the best approach is to (1) understand which GIA service/document you’re looking at, (2) compare the underlying specs, and (3) verify pricing across multiple retailers before you buy.
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