--- title: "How Are Pearls Graded?" description: "How pearls are graded: why there is no single worldwide system, how GIA's lab grades pearls, and how Japan and French Polynesia have classified them." canonical_url: "https://learnaboutpearls.com/grading/" last_updated: "2026-11-04" last_reviewed: "2026-10-26" reviewed_by: "Simon" publisher: "Unique Pearl" publisher_disclosure: "Learn About Pearls is published by Unique Pearl, a pearl jeweler." --- # How Are Pearls Graded? **Short answer:** There is no single worldwide grading system for pearls. GIA's laboratory describes natural and cultured pearls with seven value factors. French Polynesia classifies Tahitian cultured pearls by size, weight, shape and surface quality, and Japan's government once graded pearls for export. Many businesses use grading systems of their own, which CIBJO says have often been contradictory, so it matters whose scale a grade comes from. Neither [natural pearls](https://learnaboutpearls.com/glossary/#natural-pearl) nor [cultured pearls](https://learnaboutpearls.com/glossary/#cultured-pearl) have a grading system that the whole trade shares, and that shapes how any pearl grade should be read. ## Why pearls have no universal grade Many in the trade have called for a pearl grading system like the one used for diamonds. CIBJO says that is extremely difficult, because pearl quality factors are more complex and delicate than those of any other gem, personal tastes in shape and color come into it, and necklaces add the matching of many pearls. [1] Various businesses and organizations have created grading systems based on their own standards. CIBJO says these have often contradicted one another and confused the market more than they ordered it. [1] ## How a laboratory grades pearls GIA’s laboratory describes pearls using its 7 Pearl [Value Factors](https://learnaboutpearls.com/glossary/#value-factors): size, shape, color, [nacre](https://learnaboutpearls.com/glossary/#nacre), [luster](https://learnaboutpearls.com/glossary/#luster), surface and matching. [2] Its gemologists judge color, luster, surface and matching under controlled lighting against sets of master pearls, and a second gemologist repeats the observations independently. [2] A GIA report also records whether the pearls are natural or cultured, the water they grew in, the [mollusk](https://learnaboutpearls.com/glossary/#mollusk) when it can be determined, and any detectable treatments. [3] ## How governments have graded pearls **Japan.** Japan’s only quality inspection of pearls was once a government inspection of pearls for export. Pearls were rated on [nacre thickness](https://learnaboutpearls.com/glossary/#nacre-thickness), shape, luster, blemishes, flaws and finish, then given a final grade from 1 to 5, and only the top three grades passed as “H” for export. [1] **French Polynesia.** Under the territory’s pearl law, every [Tahitian cultured pearl](https://learnaboutpearls.com/glossary/#tahitian-cultured-pearl) is classified by general criteria, its size, weight, shape and [surface quality](https://learnaboutpearls.com/glossary/#surface-quality), and by additional criteria such as color, assortment, pairing and nacre thickness. [4] ## Reading a seller’s grade A grade quoted by a seller may come from the seller’s own scale, so ask which system it uses and what it measures. The page [AAA pearl grades](https://learnaboutpearls.com/grading/aaa-pearl-grades/) explains [letter grades](https://learnaboutpearls.com/glossary/#aaa-grade). For valuable pearls, a [laboratory report](https://learnaboutpearls.com/glossary/#laboratory-report) states what the pearls are as well as their quality. The [quality](https://learnaboutpearls.com/quality/) section explains each value factor. ## Start here 1. [AAA pearl grades](https://learnaboutpearls.com/grading/aaa-pearl-grades/) ## Every page in this section - [AAA pearl grades](https://learnaboutpearls.com/grading/aaa-pearl-grades/) Why letter grades like AAA aren't a standard, and how to read one. ## References 1. CIBJO Pearl Commission (2025). CIBJO Guides Describing and Classifying Natural and Cultured Pearls, the Producing Molluscs & Responsible Pearling. [Source](https://cibjo.org/wp-content/uploads/2025/12/Final-Guide-October-2025-v2-COMPRESSED.pdf) · [Archived copy](https://web.archive.org/web/20260212155210/https://cibjo.org/wp-content/uploads/2025/12/Final-Guide-October-2025-v2-COMPRESSED.pdf) 2. Gemological Institute of America (GIA), Analysis & Grading. How GIA Identifies and Classifies Pearls. [Source](https://www.gia.edu/gem-lab-how-gia-identifies-classifies-pearls) · [Archived copy](https://web.archive.org/web/20260606232640/https://www.gia.edu/gem-lab-how-gia-identifies-classifies-pearls) 3. Phoebe Shang (2026). Freshwater Akoyas – A Trending Misnomer for Certain Freshwater Pearls. [Source](https://www.gia.edu/freshwater-akoyas-a-trending-misnomer-for-certain-pearls) · [Archived copy](https://web.archive.org/web/20260617073835/https://www.gia.edu/freshwater-akoyas-a-trending-misnomer-for-certain-pearls) 4. Assemblée de la Polynésie française (Journal officiel de la Polynésie française) (2017). Loi du pays n° 2017-16 du 18 juillet 2017 réglementant les activités professionnelles liées à la production et la commercialisation des produits perliers et nacriers en Polynésie française. [Source](https://www.ressources-marines.gov.pf/wp-content/uploads/sites/24/2017/10/Loi-du-Pays-n%C2%B0-2017-16-du-18_07_2017-Activit%C3%A9s-professionnelles-perli.pdf) · [Archived copy](https://web.archive.org/web/20261026000126/https://www.ressources-marines.gov.pf/wp-content/uploads/sites/24/2017/10/Loi-du-Pays-n%C2%B0-2017-16-du-18_07_2017-Activit%C3%A9s-professionnelles-perli.pdf) **Written by:** Learn About Pearls editors **Fact-checked:** Learn About Pearls editors, October 26, 2026 **Reviewed by:** Simon, October 26, 2026 **First published:** November 4, 2026 **Publisher:** [Unique Pearl](https://learnaboutpearls.com/about/), a pearl jeweler **Revision history** 1. November 4, 2026: First published. First published **How to cite this page** **APA:** Learn About Pearls editors. (2026). _How Are Pearls Graded?_ Learn About Pearls. https://learnaboutpearls.com/grading/ **MLA:** “How Are Pearls Graded?” _Learn About Pearls_, Unique Pearl, November 4, 2026, learnaboutpearls.com/grading/. **Chicago:** Learn About Pearls editors. “How Are Pearls Graded?” Learn About Pearls. Unique Pearl. Last modified November 4, 2026. https://learnaboutpearls.com/grading/. **BibTeX:** `@misc{lap-grading, title = {How Are Pearls Graded?}, author = {{Learn About Pearls editors}}, year = {2026}, howpublished = {\url{https://learnaboutpearls.com/grading/}}, note = {Learn About Pearls, published by Unique Pearl}}` Quoting with attribution and a link is welcome. See [how to cite and reuse](https://learnaboutpearls.com/cite/). **Suggest a correction** ## Related pages - [Quality](https://learnaboutpearls.com/quality/): The seven value factors for pearls, size, shape, color, luster, surface, nacre and matching, and what each one means. - [Identification](https://learnaboutpearls.com/identification/): Telling real from imitation and natural from cultured, spotting treatments, and when to ask a lab.