Behind the Scenes of Stuller’s Diamond Screening Lab
Discover how Stuller raises industry standards with the Stuller Gemological Lab.
What does it take to sell a diamond? Of course, it must have a brilliant sparkle and hit the right price point. But, above all, there is an element of trust that is necessary to close the sale. In today’s market, there is no greater currency than trust.
Trust is built through consistency and transparency. When you provide your customers with confidence in the quality of your product and information to back it up, they trust that you are a reliable jeweler and deserve their business. Stuller goes to great lengths to provide you with diamonds that meet that expectation. Today, we are going to explore Stuller’s diamond screening capabilities and discover how this brings added value to your purchase.
Why Is Diamond Screening Important?
As lab-grown diamonds have gained popularity over the past few years, the percentage of undisclosed lab-grown diamonds has risen. An increasingly educated public has become more aware of this issue, which has fostered feelings of distrust among consumers. Undisclosed lab-grown diamonds place the entire industry at risk of losing the respect and confidence of the general public — not to mention open jewelers up to very costly lawsuits.
By raising the standards across the industry for diamond screening, we can protect our reputation as well as make sure every diamond sale is legitimate.
Pro Tip
If you want to introduce diamond screening within your own business practices, we recommend that you have two screening instruments of differing technologies to reduce error and give you a more confident identification.
Click here to learn more about diamond screeners and testers.
What Is the Stuller Gemological Lab™?
Stuller began offering lab-grown diamond products in 2012. By 2015, the market began to prompt a conversation amongst leaders to answer a very serious question: What is the percentage of undisclosed lab-grown diamonds we are willing to allow in our inventory? The answer was none.
This high standard came with a great amount of action and thus began the Stuller Gemological Lab. Across all Stuller locations around the globe, the Stuller Gemological Lab includes more than 70 instruments that are used to screen and test every loose or mounted diamond that enters our facility. This includes 16 models using 9 different technologies operated by more than 40 employees. With these extensive capabilities, we screen approximately 5.5 million diamonds every year.
As a result, we have complete confidence that we can clarify the origin of every diamond that enters our facility and stand by our zero-tolerance policy for undisclosed lab-grown diamonds. This is a confidence we happily pass on to our customers through every diamond purchase.
What is Melee Analysis by GIA®?
In 2018, Stuller embarked on a strategic service arrangement with the Gemological Institute of America. This lab is an independent entity that is currently located within Stuller’s global headquarters in Lafayette, Louisiana, and staffed by GIA employees. The partnership between Stuller and GIA is the first and only of its kind within the industry.
The Melee Analysis service by GIA has three pieces of equipment that screen up to 1,000 diamonds per hour each. They can screen any colorless round or fancy-shaped diamond up to 4 millimeters. The Stuller Gemological Lab screens every other type and size of diamond.
The greatest benefits of this arrangement have been the ability to keep up with demand and expand the screening capabilities of Stuller, which in turn provides better quality to our customers.
Established and Respected Expertise
The leadership of the Stuller Gemological Lab possesses more than 100 years of combined experience as well as top certifications from the Gemological Institute of America, the Gemmological Association of Great Britain, and other leading institutes. Through our combined efforts, we ensure consistency and accuracy in our diamond screening and testing protocols.
As pillars and pioneers in the field, we work consistently with technology brands to consult and provide feedback on the latest equipment before it hits the market. This lets us test devices our customers may one day use to ensure you’ll be in good hands. We do this because we believe in upholding the highest standards of quality and transparency across the entire industry.
Our future will continue to include peer-reviewed research that pushes us to think outside the box, stay ahead of the industry’s needs, and develop new techniques that meet the needs of jewelers.
Read: Rare Mixed Type IaB-IIb Diamond with a Long-Lasting Phosphorescence
Standards Beyond Compare

The need for trust in the marketplace grows stronger every day. While our industry consistently evolves, so must we along with it. Stuller believes in providing jewelers with the finest quality goods with an unparalleled level of service. Through our thorough, industry-leading screening protocols, we happily provide jewelers with confidence and reliability they can pass on to their customers — a truly invaluable investment.

Guy Borenstein
Director of Gemstone Procurement and Senior Gemologist
Guy holds the highest recognitions and certifications in gemology from some of the most well-respected institutions around the world, such as the Gemological Institute of America, Gemmological Association of Great Britain, and more. As Stuller's senior gemologist, he maintains the integrity of the Stuller Gemological Lab.