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Diamond Screening and Testing

Stuller Has Taken a Leadership Position

As a major supplier, we are in a position to protect our supply chain, your reputation, and your customer’s confidence. We gladly accept this responsibility by maintaining

  • A zero-tolerance policy for undisclosed lab-grown diamonds.
  • Robust in-house screening stations which test all incoming and outgoing loose and mounted diamonds.
  • Melee Analysis by GIA® — a strategic service arrangement with GIA® (an independent entity located inside Stuller facility).
  • Stuller Gemological Lab™, a state-of-the-art advanced diamond screening lab.

Understanding the Lab-Grown Market

Lab-grown diamonds (LGDs) have become increasingly popular, offering consumers highly attractive price and quality options they previously may not have been able to afford. A laboratory-grown diamond, also known as “laboratory-created,” “synthetic,” or simply “lab-grown,” is a diamond that appears identical to its natural, earth-mined counterpart. It possesses the same chemical composition and physical properties as a natural diamond. Even to the experienced professional eye, lab-grown diamonds look exactly the same as a natural diamond.

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Why is Extensive Screening and Testing Needed?

Our industry and reputations suffer when undisclosed lab-grown diamonds (ULGDs) are sold. Since 2017, the industry media has covered dozens of ULGD issues reported by leading gemological laboratories. The frequent news reported on all types of goods including loose stones, mixed melee parcels, and disclosure issues within mounted jewelry. This trend repeatedly demonstrates the increased prevalence of these cases in the market and fuels consumer awareness of the new issue.

Stuller's Screening Process

When you order diamonds from Stuller, you can have complete confidence in your purchase. We remain at the forefront of diamond screening with robust practices that use the most advanced technology available.

Our screening technology includes

  • 2 automatic melee screeners
  • 25 fluorescence imaging screeners for loose and mounted diamonds
  • 3 mega-sized imaging screeners
  • 8 fluorescence spectroscopy screeners
  • 9 UV-transparency screeners

As added security, we require our suppliers to screen all diamonds for lab-grown diamonds before shipping to Stuller. In addition, random samples of diamonds from all of our suppliers are periodically sent to leading laboratories to check for lab-grown diamonds.

By incorporating these protocols, Stuller extends confidence and security to our customers, ensuring that you are getting exactly what you purchase.

Stuller Gemological Lab

Referrals from Stuller's screening processes and the Melee Analysis by GIA are sent to the Stuller Gemological Lab for further testing. Lead by an FGA (Fellow Gemmological Association of Great Britain) certified gemologist and a team of GIA Graduate Gemologists, our lab has advanced instrumentation used by leading laboratories worldwide.

The Stuller Gemological Lab instruments include

  • Advanced analytical instruments, such as FTIR, Raman-Photoluminescence, UV-Vis-NIR, EDXRF, and fluorescence spectroscopy.
  • UV fluorescence and phosphorescence imaging instruments.
  • Advanced gemological microscopes, enhanced with unique features such as polarization, immersion, and digital imaging.
  • Numerous hand-held gemological devices and testers.

Melee Analysis by GIA®

Stuller has a strategic service arrangement with GIA (Gemological Institute of America), which is a separate entity from Stuller. It's staffed by GIA specialists who use GIA's proprietary technology to perform their work.

GIA’s equipment screens round melee diamonds in sizes 0.005 carat through 0.24 carat. After screening, their technology gives the stones a GIA color grade, the industry benchmark.

At the Forefront of Research

The Stuller team is committed to actively researching lab-grown diamond screening and detection methods, and sharing those findings with the industry. Notable research and discoveries made by our specialists have been published by the most respected scientific journals of the industry, positioning Stuller as a pioneer in the field .

Some of our team contributions include

  • Selecting a Diamond Verification Instrument Based on the Results of the Assure Program - An Initial Analysis Journal of Gemmology; 2019, Vol. 36, Issue 7
    View PDF
  • 3 Near-Colourless HPHT-grown Synthetic Diamonds that Test as Synthetic Moissanite Journal of Gemmology; 2021, Vol. 37, Issue 6
    View PDF
  • Rare Mixed Type IaB-IIb Diamond with a Long-Lasting Phosphorescence Gems and Gemology; Summer 2021, Vol. 57, No. 2
    View PDF

Stuller’s Senior Gemologist Discovers An Extremely Rare Diamond

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5/25/2022 Market Prices:
Gold 1847.20 Platinum 954.00 Silver 21.83