The Young Durability Scale is a Landmark Advancement for Gemology

A groundbreaking scale that redefines gemstone durability by combining hardness, fracture toughness, and inclusions into a comprehensive framework for the gem and jewelry trade.

BURLINGTON, Vt., Oct. 1, 2025 /PRNewswire/ -- A breakthrough in gemstone science has arrived with the introduction of Young's Durability Scale, a comprehensive new framework for evaluating the durability of jewelry-quality gemstones. Developed by gemologist Kennon Young, GG, CBJT, ASA-MGA of the Vermont Gemological Laboratory, this innovative scale addresses one of the most long-standing challenges in gemology: understanding and measuring durability beyond hardness. For centuries, the Mohs scale has been the dominant reference for gemstone wearability, yet it has been widely misapplied as a proxy for durability. Young's Durability Scale represents a paradigm shift, moving the field of gemology toward a deeper and more nuanced understanding of how gemstones behave under stress. For nearly two centuries, jewelers, gemologists, and consumers have relied heavily on the Mohs scale of hardness, created in 1812 by Friedrich Mohs, to evaluate a gemstone's ability to withstand wear. However, as Mohs himself observed, "The degree of hardness, however, cannot be the sole determinant of a mineral's resistance to wear or destruction. Many minerals, though quite hard, are very brittle and may fracture or cleave easily, while others, though not particularly hard, exhibit remarkable toughness and resilience. Thus, hardness and durability must not be confused." The Young Durability Scale builds on this wisdom by providing a probabilistic, weighted model that accounts for multiple factors, moving beyond the limitations of hardness alone. It reflects decades of research and the latest scholarship, integrating insights from crystallography, material science, and practical jewelry design.

The scale integrates three essential elements into a single framework: hardness, fracture toughness, and inclusions. Each element plays a critical role in determining a gemstone's ability to resist wear and damage. Hardness, holds 35 percent importance in the scale, evaluates resistance to surface scratching and is based on the Moh's hardness scale. Fracture toughness, which carries the heaviest weight at forty-five percent, measures resistance to chipping, cracking, and cleavage, making it the most predictive factor for real-world jewelry damage. Inclusions, making up twenty percent of the scale, assesses how internal features within a gemstone either weaken or enhance its structural integrity, with the scoring system accounting for frequency, distribution, and interaction with cleavage planes. The combination of these elements into a weighted model produces a durability ranking that more accurately reflects how gemstones perform in everyday jewelry use. By synthesizing these aspects into a single matrix, Young's Durability Scale provides a clearer, more reliable view of durability than any system that has come before it.

The results of this approach have been both fascinating and sometimes surprising. Nephrite jade, for example, ranks at the very top of the scale due to its exceptional toughness and fibrous polycrystalline structure, achieving a higher overall durability score than diamond. This finding underscores why jade has been used for millennia in tools, weapons, and ceremonial objects that required resilience as much as beauty. Diamond, while unmatched in hardness, receives a lower durability ranking because of its susceptibility to cleavage and the weakening effects of certain inclusions. This explains why diamonds, though prized for their brilliance and wear resistance, can still break or chip when struck at the wrong angle. Stones such as opal and fluorite fall at the lower end of the scale, reflecting their well-documented fragility and high likelihood of damage under normal wear conditions. These rankings are not only scientifically significant but also immensely practical for those who buy, sell, and set gemstones. They provide a much-needed framework for predicting long-term wear and for guiding consumers in their choices of jewelry for their desired application.

The implications of Young's Durability Scale extend far beyond academic interest. For jewelers, the scale offers guidance on which gemstones are most suitable for high-wear jewelry such as rings and bracelets, and which should be reserved for pieces like pendants and earrings where exposure to knocks and abrasion is reduced. For designers, the scale provides a scientific foundation for selecting materials that balance beauty with functionality, ensuring that their creations can stand the test of time. Collectors and auction houses gain a reliable standard for assessing risk and value when handling rare and high-value gems. Insurance companies can make more accurate risk assessments of jewelry coverage. Even consumers benefit from this tool, as it empowers them to make informed decisions when investing in fine jewelry and to understand the care and precautions required for different gemstones. For retailers, the scale provides a valuable sales tool, offering a clear and scientifically grounded way to educate clients about durability concerns. By incorporating the scale into their sales presentations, retailers can strengthen customer confidence, better manage expectations, and foster greater trust in their expertise and in the products they sell. "This model finally gives the jewelry industry a practical, science-backed way to evaluate gemstone durability that goes far beyond scratch resistance," said Kennon Young. "It's a tool that empowers everyone, from bench jewelers to auction houses, to make better-informed decisions about gemstone use, care, and long-term value." His work helps dismantle common misconceptions, such as the notion that hardness alone can predict performance, while offering a more comprehensive understanding rooted in real-world application. In this sense, the Young Durability Scale is not only a scientific breakthrough but also a practical resource that bridges the gap between laboratory research and the jewelry counter.

Young's Durability Scale was reviewed by Al Gilbertson of the Gemological Institute of America (GIA) and presented at GIA's Poster Session during Converge, where it was recognized as a vetted contribution to the field. This advancement represents a significant step forward in how the industry understands gemstone performance. The model doesn't include every gemstone, as some data isn't available. Tourmaline, for example, has never been tested for fracture toughness. It also does not attempt to describe every possible scenario but instead focuses on the statistically probable behavior of gem species under typical conditions of use. By doing so, it offers an accessible and highly relevant framework for jewelers, gemologists, designers, retailers, collectors, and consumers alike. Its careful balance of empirical research and practical applicability ensures it will become a cornerstone resource for years to come.

The launch of Young's Durability Scale arrives at a pivotal moment for the jewelry industry. As consumer demand grows for transparency, scientific rigor, and ethically sourced materials, tools like this reinforce trust and confidence in gemological expertise. Moreover, as jewelry design increasingly incorporates unconventional materials and experimental settings, having a reliable framework for durability is more critical than ever. Young's model provides the clarity and consistency needed to support innovation while safeguarding the longevity of precious pieces. By grounding gemstone evaluation in probability and weighted performance factors, the scale sets a new standard for how durability is understood and communicated across the trade. With its introduction, Young's Durability Scale is poised to reshape the way jewelers, gemologists, retailers, and consumers evaluate gemstones. It provides clarity where confusion once reigned, offering new insights into the relationship between gemstone properties and their practical durability. As jewelry design continues to evolve, and as consumers demand more transparency and knowledge about the gems they purchase, this scale could become a defining standard for evaluating gemstone resilience and longevity. For the first time, the industry has a tool that accounts for the complexity of gemstone structures and the interplay of their physical properties, delivering a level of understanding that aligns both with science and with the realities of jewelry wear.

To learn more about the Vermont Gem Lab visit https://www.vermontgemlab.com/ or call 802-862-6600. For inquiries about this press release, contact Pietra Communications at [email protected] or call 212-913-9761.

About Kennon Young

Kennon Young, GG, CBJT, ASA-MGA, has dedicated his entire professional career to the jewelry industry. His journey began with four years of jewelry electives in high school, which inspired him to pursue formal training at the Revere Academy of Jewelry Arts in San Francisco in 2000. There, he completed the Graduate Jeweler program, participated in the Master's Symposium, and earned a Jeweler's of America Bench Jeweler Certification, building a strong foundation in jewelry manufacturing.

His growing passion for gemstones led him to the Gemological Institute of America in San Diego, where he became a Graduate Gemologist with a specialty in design. Young continued to expand his expertise through a multi-year study of valuation in personal property at the Rhode Island School of Design Extension. In 2016, he achieved one of the highest credentials in the appraisal profession, the American Society of Appraisers' Master Gemologist Appraiser accreditation. That same year, the Vermont Gem Lab, which he founded in Burlington, VT, became a Certified Gemological Laboratory through the American Gemologists Association. Since 2004, Young has operated the Vermont Gem Lab, specializing in custom-designed engagement rings, restoration of antique jewelry, and advanced estate valuations. In 2019, he launched Starlust Jewelry, a personal passion project that draws on ancient zodiac symbols to create meaningful jewelry connecting loved ones through timeless symbolism.

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SOURCE Vermont Gem Lab