Testing Lab-Grown Diamonds: What You Need to Know

October 17, 2024

The rise of lab-grown diamonds has transformed the jewelry industry, offering consumers an ethical and affordable alternative to mined diamonds. However, this shift has also posed new challenges for the tools used to verify a diamond’s authenticity. Lab-grown diamonds, like moissanite, have evolved, and so too have the testing methods designed to differentiate them from natural diamonds. Understanding the history of diamond testers, the latest innovations, and the limitations in current testing methods is crucial for jewelers and consumers alike.

History of Diamond Testers

Diamond testers have been an essential tool in the jewelry industry for decades. Traditionally, these devices relied on thermal conductivity to distinguish diamonds from other stones like cubic zirconia (CZ) or glass. Diamonds are excellent conductors of heat, and these testers would measure how quickly heat moved through the stone.

For many years, this method worked well - until moissanite entered the market. Moissanite, a lab-grown gemstone with remarkable brilliance, also conducts heat similarly to diamonds. This created confusion, as early diamond testers could not distinguish between moissanite and natural diamonds.

New Testers Developed in Response to Moissanite

The introduction of moissanite prompted the development of a new generation of diamond testers, which combined thermal conductivity with electrical conductivity measurements. Unlike diamonds, moissanite has a higher electrical conductivity, making it possible to tell the two apart. These new testers helped jewelers differentiate between moissanite and natural diamonds more accurately, addressing the initial flaw in traditional testing.

However, the rise of lab-grown diamonds - which are chemically and physically identical to mined diamonds - added a new layer of complexity. Most lab-grown diamonds, whether produced through High Pressure High Temperature (HPHT) or Chemical Vapor Deposition (CVD), can easily pass these diamond tests. This is because they possess the same thermal and electrical properties as natural diamonds, making it nearly impossible for conventional testers to distinguish them.

Flaws in the Way Diamond/Moissanite Testers Work

While current diamond/moissanite testers have improved, they still exhibit several flaws, particularly when testing for lab-grown diamonds. Some key issues include:

Inability to Differentiate Lab-Grown from Natural Diamonds: Since lab-grown diamonds are real diamonds, traditional testers (even those designed to differentiate between diamonds and moissanite) cannot detect their origin. These devices do not test for the specific growth process (natural or lab-created) but only for the physical properties common to both types of diamonds.
False Positives with Moissanite: In some cases, moissanite can still confuse testers, especially if the tool relies solely on thermal conductivity. Jewelers must use more advanced methods or a combination of testers to ensure accuracy.
Similar Properties: As moissanite continues to evolve and more sophisticated lab-grown diamonds emerge, these gems challenge the capabilities of basic testers. Jewelers need to remain up-to-date with the latest testing technologies to avoid misidentifying stones.

Advanced Testing for Lab-Grown Diamonds

With the limitations of traditional testers, gemological labs have developed advanced methods to accurately identify lab-grown diamonds. These include:

Spectroscopy: This method analyzes the light absorption and emission patterns of diamonds. Lab-grown diamonds often display different spectral patterns compared to natural diamonds due to slight variations in their crystal structure.
Fluorescence Testing: Some lab-grown diamonds exhibit stronger fluorescence under ultraviolet light compared to natural diamonds. This can provide clues to their origin.
Phosphorescence: HPHT-grown diamonds sometimes exhibit phosphorescence, glowing faintly after exposure to ultraviolet light. This characteristic can help distinguish them from mined diamonds.
Inclusions and Growth Patterns: Lab-grown diamonds may have unique internal features, such as metallic inclusions or distinct growth patterns, that are not found in natural diamonds. These can be detected using magnification tools like a jeweler’s loupe or a microscope.

Moissanite Also Passes the Diamond Test

One of the main challenges in testing remains moissanite, as it can pass many standard diamond tests. This gemstone has physical properties that closely resemble those of diamonds, particularly in terms of brilliance and fire. Although testers that measure both thermal and electrical conductivity are available, moissanite’s growing popularity in the market makes it essential to combine testing techniques to ensure proper identification.

Consumers should be aware that moissanite is not a diamond, but it is a stunning alternative, offering durability and brilliance at a more affordable price. For those seeking diamond-like beauty without the cost or environmental concerns, moissanite remains a top contender. However, it is essential to understand that traditional diamond testers may not always provide a clear distinction between moissanite and lab-grown or natural diamonds.

In Conclusion

Testing lab-grown diamonds requires a deeper understanding of the tools and methods used by jewelers. While thermal and electrical conductivity testers have been instrumental in differentiating diamonds from other stones, the rise of lab-grown diamonds and moissanite has exposed flaws in traditional testing techniques. Today’s jewelers must rely on more advanced methods, such as spectroscopy and fluorescence, to ensure they can accurately identify lab-grown diamonds.

For consumers, being informed about the testing process is key to making confident and ethical choices. Whether you’re investing in a lab-grown diamond or exploring moissanite as an alternative, understanding how these stones are tested can help you make an informed decision.

FAQs About Testing Lab-Grown Diamonds

1: What is the history of diamond testers?
Diamond testers have been used in the jewelry industry for decades, primarily relying on thermal conductivity to distinguish diamonds from other materials. Initially, these testers were effective in identifying natural diamonds versus stones like cubic zirconia (CZ) or glass. However, with the introduction of moissanite, which exhibits similar thermal properties to diamonds, traditional testers faced challenges in accurately differentiating between the two.

2: How have testers evolved in response to the introduction of moissanite?
In response to the confusion caused by moissanite, a new generation of diamond testers has been developed. These advanced testers combine thermal and electrical conductivity measurements, allowing jewelers to differentiate moissanite from natural diamonds more accurately. This innovation has greatly improved the ability to identify various types of stones in the market.

3: What are the flaws in the way diamond/moissanite testers work?
Despite advancements in testing technology, there are still significant flaws. Traditional testers cannot differentiate between lab-grown diamonds and natural diamonds, as both possess identical physical properties. Additionally, some testers may yield false positives with moissanite, leading to potential misidentification. Jewelers need to use more sophisticated techniques to ensure accurate results.

4: What advanced methods are used to test lab-grown diamonds?
Advanced testing methods include spectroscopy, fluorescence testing, and examining inclusions and growth patterns. Spectroscopy analyzes the light absorption characteristics of the diamond, while fluorescence testing can reveal differences in luminescence between lab-grown and natural diamonds. Additionally, gemologists look for unique internal features that may distinguish lab-grown diamonds from their natural counterparts.

5: How does moissanite pass the diamond test?
Moissanite can pass many standard diamond tests due to its similar physical properties, particularly brilliance and fire. While some diamond testers measure both thermal and electrical conductivity, they may not effectively identify moissanite in certain situations. Jewelers are encouraged to combine testing methods for accurate identification, ensuring they understand the distinctions between moissanite and diamonds.

6: Should consumers be concerned about the testing process for lab-grown diamonds?
Yes, consumers should be informed about the testing process, as it can affect their purchasing decisions. Understanding the limitations of diamond testers and the different types of stones available in the market, including lab-grown diamonds and moissanite, empowers consumers to make confident and ethical choices regarding their jewelry investments.