Diamond Testers  

Growing rapidly in popularity among young consumers, lab-grown diamonds are a vibrant topic of conversation these days. They have been in the jewelry industry since the 1980s, but their growth in the market in recent years has been exponential. 

According to analysts with The MVEye, a market research and strategic consulting firm within our industry, more than 70% of retailers now offer lab-grown diamonds. Additionally, lab-grown diamonds currently make up approximately 10% of the global diamond market with a vast majority of that existing in the United States. While that may not seem like a significant number, that percentage has grown from 1% in 2018. So how do we as jewelers maintain integrity in our market and keep the trust of our customers?

With the rising number of lab-grown diamonds in the jewelry industry, it must be every jeweler’s responsibility to educate themselves on lab-grown diamonds, have access to reliable diamond testing and screening, and purchase diamonds from trustworthy sources. 

Natural vs. Lab-Grown Diamonds 

Diamonds used in jewelry are either naturally mined from the earth or grown in a laboratory setting. Natural diamonds are formed over millions to billions of years and possess a unique rarity that contributes to their value. Lab-grown diamonds can be created from several hours to a few weeks in a controlled setting using one of two different methods. 

The High Pressure High Temperature (HPHT) method mimics the natural growing process by applying heat and pressure to a graphite to accelerate growth of the crystalized diamond. Chemical Vapor Deposition (CVD) alternatively uses a chemical vapor to stimulate growth of a diamond crystal from a carbon-rich gas. 

Optically, chemically, and physically, both natural and lab-grown diamonds are identical to each other and cannot be identified by sight. Advanced instruments, such as spectrometers and imaging systems, are required to help make that distinction. 

Diamond Simulants

While on the topic of discussing natural and lab-grown diamonds, diamond simulants must also be mentioned. A diamond simulant is a natural or man-made gemstone that mimics the appearance of a diamond, such as Cubic Zirconia, Moissanite, White Sapphire, and White Topaz. 

Gemstones like these are often used in jewelry to provide the luxurious appearance of diamonds but at a significantly lower price point. While there are subtle optical differences in some of these gemstones, it is important to be certain of identity when working with colorless stones. 

Diamond Testing vs. Screening

According to guidelines from the Federal Trade Commission, it’s the responsibility of the jeweler to provide factual disclosure on the nature of diamonds and gemstones (natural vs. lab-grown vs. simulant). It’s on you to know the differences and know what you’re selling. The best way to give yourself that confidence is through diamond testing and screening. 

Though similar in nature, these are two separate processes that are equally important. Diamond testing is the process of separating diamonds from simulants, such as Moissanite and Cubic Zirconia. The diamond testers that are used in this process measure the thermal and/or electrical conductivity of the gemstone, and check if it fits the properties of a diamond. 

Diamond screening is the process of separating natural diamonds from lab-grown diamonds. Screening is not the same as identification. Screeners will either help confirm identity of a natural diamond or refer the diamond for further screening. 

As a jeweler, the best practice to take is to at minimum have a diamond tester and a diamond screener in your shop. However, the ideal situation is that you have a diamond tester and two diamond screeners. It’s always best to screen an apparent diamond with two instruments using different technology. That way you can back up the limitations of different equipment for more confident identification, and you reduce error.  

Tools for the Job

Stuller offers an assortment of diamond testers and screeners where you have options. Below are recommendations from our team on our preferred screeners and testers. Each of these items is ASSURE tested, which means they have undergone one of the most stringent third-party accuracy tests available.  

The GIA® iD100® (29-3020) is a diamond screener that is built to identify natural diamonds with near certainty. It is the only diamond screener Stuller offers capable of working with both colorless (or near-colorless) as well as colored (blue, green, and brown) diamonds. Pink diamonds can also be tested with a GIA® software update.  

The DiaTrue CS2 (40-4040) can provide interpretive results where you can easily identify natural diamonds and lab-grown diamonds created through HPHT. Lab-grown diamonds created through CVD, Moissanite, and Cubic Zirconia can be referred for further tests.

The Gemlogis Belize (56-2020) is one of the most innovative pieces of equipment on the market. It functions as a screener as well as a tester and is handheld for ease of use. 

The ARI by Presidium® (54-5454) uses the same technology as the Gemlogis Belize, but with the screening mode only.

Practicing What We Preach 

Stuller has a reputation for taking a leadership position as a major supplier of natural and lab-grown diamonds. We do not tolerate undisclosed lab-grown diamonds in our inventory and go to great lengths to accurately screen and test every diamond that enters our facility. The Stuller Gemological Lab™ as well as a strategic partnership through GIA® with Melee Analysis by GIA® helps us ensure this goal. You can learn more about our diamond screening and testing processes on our website.

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Diamond authenticity is a crucial topic within our industry. As jewelers, consumers look to us to make sure they get what they pay for and their investment in fine jewelry is legitimate. By taking the time to understand the diamond market and invest in the right equipment, you can better serve your customers as a trusted source and maintain the integrity of our industry.  

This article was written in partnership with Harold Dupuy, Guy Borenstein, and Sean O’Neal as subject-matter experts in diamond screening and testing as well as lab-grown diamonds in the marketplace.