Precise, IndependentDiamond Certification
Science-backed grading trusted by retailers, buyers, insurers, and auction houses worldwide.
The Grading Process
At UGL, our Natural Diamond Certification provides precise and independent assessments using the industry's most advanced gemological instruments.
Rigorous, Multi-Step Analysis
When a natural diamond arrives at UGL, it undergoes a rigorous analytical process designed to guarantee complete objectivity.
Stones are first weighed using calibrated analytical micro-balances, then proceed to our spectroscopy labs for fluorescence and transparency diagnostics. Finally, senior gemologists perform the comprehensive 4Cs assessment under strictly controlled, standardized lighting environments.
What We Assess
We grade diamonds strictly using the internationally accepted 4Cs system — the global language of diamond quality.
Cut
Evaluating exact proportions, symmetry, and polish to scientifically measure the stone's brilliance, fire, and scintillation.
Color
Grading on the universal D-to-Z scale using master comparison stones, under strictly controlled lighting conditions.
Clarity
Assessing inclusions and blemishes under 10x binocular magnification, plotted on a detailed diagram.
Carat
Measuring exact weight to the fifth decimal place using calibrated analytical micro-balances.
Why Our Certification Matters
In a market where precision is paramount, UGL represents trust. Our science-backed grading translates into clear reports trusted globally.
Blind Grading Protocol
Client data is obscured from graders during assessment — guaranteeing zero bias, every time.
Global Recognition
Our certificates are trusted by retailers, buyers, insurers, and auction houses in 95+ countries.
Protects Your Investment
Our compliance with international standards provides enduring peace of mind and real financial protection.