Diamond Testing and Grading
Diamonds have garnered adoration not only for their inherent qualities such as color, brilliance, clarity, hardness, and rarity but also due to the enduring marketing slogan, “diamonds are forever.”
These precious gemstones are naturally formed under extreme high temperature and pressure deep beneath the Earth’s surface over billions of years, and they occur in various colors including colorless, yellow, blue, green, pink, brown, and black.
The value of diamonds is influenced by multiple factors, with rarity playing a significant role, particularly for colored diamonds. Internationally adopted, the grading score for diamonds encompasses the 4Cs: carat weight, clarity, color, and cut.
Synthetic (lab-grown) diamonds have become increasingly prevalent in the retail market in recent years, through High Pressure and High Temperature (HPHT) and Chemical Vapor Deposition (CVD) process grown in laboratory settings.
For instance, CVD-grown diamonds can be obtained in various sizes, up to 30 carats and exhibit colorless hues with near-flawless clarity, making them incredibly difficult to differentiate from naturally occurring diamonds using standard gemological instruments.
At NGI, with cutting-edge and state-of-the-art testing instruments, ensuring that we possess the complete capability to test and grade diamonds with utmost accuracy and precision.
Our main activities are :
- Identify natural diamond (sometimes with the type I and II ) and lab-grown diamonds (HPHT and CVD ) by applying combination of experience and advanced scientific instruments analysis such instruments are Raman spectrometry, Photoluminescence PL etc
- Determine whether the color of a diamond has been altered through the HPHT process. For example, a pink-colored diamond may be the outcome of treating a brown diamond using the HPHT process
- Grade a diamond based on 4 Cs, and other characteristic eg. polish finishing, cut symmetry & its fluorescence
- Issue diamond report with full grading details in accordance with international standards, (Gemological Institute of America, GIA)
- Verify the diamond authenticity against the owner’s original diamond report
- Identify lab-grown melee diamond with the aid of various instruments including fluorescence
For More Stone Options And Information, Please Reach Out To Us
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