In a significant development for the pearl industry, the Gemological Institute of America (GIA) has announced the implementation of a new, expanded nacre grading scale across all pearl classification reports. This enhancement marks an evolution in the GIA’s renowned pearl evaluation framework, the GIA 7 Pearl Value Factors™, aimed at providing more refined insights into nacre quality.
Historically, nacre—an essential component influencing a pearl’s beauty and durability—was graded simply as either “Acceptable” or “Unacceptable.” While “Acceptable” signified commercially viable nacre in terms of thickness and condition, “Unacceptable” referred to nacre that posed risks to the pearl’s longevity due to flaws such as chalkiness, excessive thinness, or physical damage.
Responding to feedback from international pearl industry stakeholders, GIA’s revamped approach offers a more detailed analysis, evaluating nacre with a five-tier scale: Excellent, Very Good, Good, Fair, and Poor. This nuanced system provides greater transparency and alignment with how other pearl value factors are assessed.
The updated nacre scale stems from extensive research involving a broad spectrum of pearl specimens, encompassing varied surface and sub-surface characteristics. The goal was to better capture the range of nacre development and consistency observed during pearl formation. Moving forward, the majority of pearls evaluated under this new system will receive a “Good” rating, replacing the previous “Acceptable” designation.
Pearl items—including single pearls, strands, and jewelry pieces—will be assessed based on visible nacre variations, post-harvest conditions (such as wear or treatment), and industry benchmarks for nacre thickness. These elements collectively determine the nacre quality noted in the GIA report.
“Nacre is fundamental to a pearl’s identity, impacting everything from luster and shape to its structural integrity,” said Tom Moses, GIA Executive Vice President and Chief Laboratory and Research Officer. “By refining our nacre classification scale, we’re providing a more accurate and comprehensive evaluation that benefits both our clients and the broader trade.”
This enhancement reinforces GIA’s commitment to advancing gemological standards while ensuring its pearl reports remain authoritative tools for buyers, sellers, and collectors worldwide.
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