Moissanite’s ability to sometimes “pass” a traditional diamond tester has raised questions and discussions among both gem enthusiasts and professionals. In this comprehensive guide, we explore the scientific principles behind why moissanite can mimic diamond characteristics on basic testers, delve into real-world examples and evolving testing technologies, and offer practical advice for accurate gemstone identification.
Understanding Thermal Conductivity
Traditional diamond testers primarily measure thermal conductivity—the ability of a material to conduct heat. Diamonds are exceptional thermal conductors, which is why testers were originally designed to detect this property.
According to Brilliant Earth, “Moissanite has a thermal conductivity that is very similar to diamond, which means it can register as a diamond on standard diamond testers that only measure thermal conductivity” [1]. This similarity in thermal properties creates the fundamental challenge in distinguishing between these two gemstones using basic testing equipment.
Dr. James Shigley, Distinguished Research Fellow at the Gemological Institute of America (GIA), explains: “The thermal conductivity of moissanite is close enough to diamond that it can produce a positive reading on many commercial diamond testers” [8]. This scientific reality means that relying solely on thermal conductivity testing is insufficient for definitive identification.
Advanced Testing Techniques
Multi-Testing: Thermal and Electrical Conductivity
While basic testers rely on heat transfer, advanced instruments incorporate electrical conductivity measurements to differentiate gemstones more reliably.
“Diamond and moissanite have different electrical conductivity properties,” notes Cullen Jewellery in their educational materials. “Multi-testers that measure both thermal and electrical conductivity can accurately distinguish between the two gemstones” [5].
Espling Jewelers further elaborates: “Modern diamond testers often combine thermal and electrical conductivity measurements to provide more accurate results. When both properties are tested simultaneously, moissanite will typically show high thermal conductivity but different electrical conductivity than a natural diamond” [6].
Evolving Technology in Gemstone Testing
Recent developments in moissanite production have introduced variants with different electrical properties, presenting new challenges for testing equipment.
As QuickTest reports, “Some newer moissanite formulations have been developed with lower electrical conductivity, which can potentially confuse even dual-testing equipment that is not regularly updated” [9]. This ongoing evolution in both gemstone production and testing technology creates a continuous need for advancement in identification methods.
Martin Jewelry adds: “The technology used in diamond testers must continually evolve to keep pace with innovations in lab-grown and simulant gemstones. Today’s most reliable testers incorporate multiple testing methods and regular software updates” [4].
Visual and Practical Cues
Visual Identification
Beyond technological testing, several visual characteristics can help distinguish moissanite from diamonds:
- Sparkle and Fire: “Moissanite exhibits greater ‘fire’ (the colorful flashes produced when light disperses through the stone) than diamond,” explains Diamond Rensu. “This heightened dispersion—2.4 times that of diamond—creates more rainbow-colored flashes that are visible even in dimmer lighting conditions” [10].
- Double Refraction: Jewellery World notes: “Moissanite is doubly refractive, meaning light traveling through the stone is split into two rays, creating a subtle doubling effect of facets that can be observed with proper magnification. Diamonds are singly refractive and do not exhibit this characteristic” [8].
- Weight Difference: “Moissanite is approximately 15% lighter than diamond of the same size,” according to Brilliant Earth. “This weight difference can be detected by experienced jewelers when handling the stones” [1].
Professional Evaluation
Despite the availability of advanced testers and visual guidelines, consulting a professional jeweler remains invaluable.
A jewelry appraiser on Reddit emphasizes: “We use a combination of testing methods in our lab—dual-property testers, microscopic examination, and spectroscopic analysis for unusual cases. No single test is foolproof, which is why professional assessment is crucial for valuable stones” [2].
Another gemologist shared on a forum: “I’ve been in the industry for 15 years, and I still occasionally encounter stones that require multiple testing methods to identify conclusively. The technology is constantly improving, but there’s no substitute for experience and professional equipment” [3].
Practical Advice for Consumers
When purchasing diamond jewelry or evaluating existing pieces, consider these expert recommendations:
- Request Documentation: “Always ask for a certificate from a reputable gemological laboratory such as GIA or IGI when purchasing diamond jewelry,” advises Cullen Jewellery. “These certificates verify the stone’s composition through comprehensive testing” [5].
- Multiple Testing Methods: Diamond Rensu recommends: “If you’re using a home tester, opt for one that measures both thermal and electrical properties. Even then, consider the results preliminary and seek professional confirmation for valuable pieces” [10].
- Understand Limitations: “Be aware that no single testing method is infallible,” warns QuickTest. “The most reliable approach combines technological testing with visual examination by a trained professional” [9].
Conclusion
Moissanite can indeed pass a basic diamond tester due to its high thermal conductivity, a property it shares with diamonds. However, advancements in testing technology—particularly those that measure both thermal and electrical conductivity—provide a more reliable method for differentiation.
As gemstone production techniques continue to evolve, testing methods must keep pace. For the most accurate identification, using a multi-property tester and seeking professional advice is highly recommended. Staying informed through reputable sources becomes essential for both consumers and professionals in the jewelry industry.
References
[1] Brilliant Earth – Does Moissanite Pass a Diamond Tester?
[2] Reddit – Why Are Diamond Testers Inaccurate?
[3] Reddit – Does Moissanite Always Test as a Diamond?
[4] Martin Jewelry – Are Diamond Testers Accurate?
[5] Cullen Jewellery – Can Moissanite Pass a Diamond Tester?
[6] Espling Jewelers – Are Diamond Testers Accurate?
[7] YouTube – Visual Demonstrations of Diamond Testing
[8] Jewellery World – Demystifying Diamond Testers
[9] QuickTest – Distinguishing Diamond from Moissanite
[10] Diamond Rensu – Does Moissanite Pass a Diamond Tester?
