Lab-Grown Diamond Screening

Posted on August 31, 2022 by Guy Borenstein, FGA EGG Senior Gemologist, Stuller Inc.

It possesses virtually the same chemical composition and physical properties as its natural, earth-mined counterpart.

During the past decade, thanks to advancements in the lab-grown diamond’s growth technology, lab- grown diamonds have become increasingly popular, offering consumers attractive price and quality options they previously may not have been able to afford.

In recent years, the industry media has covered dozens of improper disclosure and stone swapping issues reported by jewelers and leading gemological institutes. The frequent news reported on all types of goods, including loose stones, mixed melee parcels, mounted jewelry, and estate antique items. This trend repeatedly demonstrates the increased prevalence of these cases in the market and fuels consumer awareness of the new issue.

The main drive for these practices is the lack of easy identification. The continuous improvement in the color, clarity, and size of the lab-grown diamonds generated extreme difficulty visually identifying them, even by an experienced gemologist using magnification.

Moreover, traditional handheld thermal and electrical conductivity probes, known in the trade as “diamond testers,” and other basic gemological tools used by the trade for years, have proved ineffective for such stones.

Lab-grown diamonds can only be identified correctly using advanced techniques that unveil properties invisible to the human eye. These new effective techniques command deep scientific understanding and access to state-of-the-art spectrometers and imaging instruments that can record and dis- play the diagnostic features.

For the individual jeweler (or gemologist/appraiser), gaining such a scientific laboratory expertise level is virtually impossible in terms of budget and knowledge. Therefore, a series of simplified versions of the comprehensive instruments were introduced to the market to ease the trader’s daily work and overcome the knowledge barrier. The more affordable tools, occasionally called “screeners,” aim to serve the average re- tailer. Their concept is simple: One does not need to under- stand the science behind it—the device will give a simple visual (color-coded) or binary (Pass/Refer) answer.

Most screeners’ goal is straightforward.They are designed to inspect one property unique to natural or lab-grown diamonds. Basically, the majority of instruments are trying to identify properties related to nitrogen defects within the diamond’s atomic structure.

FIGURE 3. iD100 (left) and EXA (right).

Nitrogen atoms can be found in many formations within a diamond. Some of these arrangements, such as a cluster of nitrogen atoms, result from a slow process taking millions of years. Therefore, aggregated nitrogen defects within a diamond prove that the stone is of a natural origin. These structures, known as “Type Ia,”make up 98% of natural diamonds.

On the other hand, less than the remaining 2% of natural diamonds…

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