Independent Diamond Certification · New York City
Certified with Precision.Trusted with Confidence.
TGS Diamond Grading provides independent, expert certification for lab grown diamonds — giving our clients the clarity and assurance they deserve before every purchase.
How Certification Works
A rigorous, transparent process — from submission to certified report.
Submit your lab grown diamond through our secure intake process. Each stone is logged, catalogued, and assigned a unique tracking number.
Our certified gemologists evaluate every stone against the 4Cs — cut, color, clarity, and carat — using calibrated laboratory instruments.
Each assessment undergoes a secondary review to ensure accuracy and consistency before any report is issued.
A comprehensive grading report is issued, documenting every characteristic of your diamond with precision and authority.
Our Services
Certification solutions designed for jewelers, dealers, and the trade.
Full Grading Report
A comprehensive evaluation covering all 4Cs, fluorescence, measurements, and a detailed clarity plot. The gold standard for diamond certification.
Standard turnaround: 7–10 business days
Express Certification
The same rigorous grading process, prioritized for faster turnaround. Ideal when timing matters without compromising accuracy.
Express turnaround: 2–3 business days
Verification Service
Confirm the accuracy of an existing certificate or authenticate a previously graded stone. Peace of mind for secondary market purchases.
Results within 5 business days
"Independent grading isn't a formality. It's the foundation every trade transaction should be built on.
Why TGS
TGS Diamond Grading was founded on a single principle: the jewelry trade deserves rigorous, independent certification that they can on. As lab grown diamonds become a mainstream choice, the need for trustworthy, unbiased grading has never been greater. Our New York City laboratory operates independently of any retailer or manufacturer — ensuring every report reflects the stone, not a sales agenda.
Learn about TGS
Ready to Certify Your Diamond?
TGS works exclusively with trade professionals. Submit your information to open a trade account and access our certification services.