Enhance Your Jewelry Knowledge: GIA's New Pearl Classification System

The Gemological Institute of America (GIA) has revised its system for classifying pearls, specifically refining how it grades nacre in its reports. The updated method assesses nacre based on the visible movement or variation observed on both the surface and subsurface layers, alongside factors like wear, damage, treatments, modifications, and adherence to industry standards for thickness. Instead of the previous “acceptable” or “unacceptable” categories, nacre now falls into one of five levels: “excellent,” “very good,” “good,” “fair,” or “poor,” which will be clearly indicated on all GIA pearl reports.

This change was driven by a thorough analysis of various pearl samples, focusing on surface and internal features that reveal differences in nacre layering and growth continuity. According to Tom Moses, GIA’s Executive Vice President and Chief Research Officer, nacre plays a vital role in a pearl’s development, influencing its size, shape, luster, surface quality, and durability. The new grading scale offers a more precise description of nacre quality, enhancing the overall pearl evaluation process.

As a result of this update, most pearls submitted for grading will now be classified as having “good” nacre, replacing the previous “acceptable” category. The revision responds to feedback and requests from industry members worldwide, aiming to improve clarity and accuracy in pearl grading.

https://www.gia.edu/gem-lab-service/pearl