--- title: "Natural vs Cultured Pearls: What's the Difference?" description: "Natural and cultured pearls compared: how each one forms, how rare natural pearls are, how labs tell them apart, and how each is named and weighed." canonical_url: "https://learnaboutpearls.com/compare/natural-vs-cultured-pearls/" last_updated: "2026-11-04" last_reviewed: "2026-11-01" reviewed_by: "Simon" publisher: "Unique Pearl" publisher_disclosure: "Learn About Pearls is published by Unique Pearl, a pearl jeweler." --- # Natural vs Cultured Pearls: What's the Difference? **Short answer:** A natural pearl forms inside a mollusk with no human help, while a cultured pearl forms after a person implants a bead or a piece of tissue. Both are grown by living mollusks, unlike imitations, but natural pearls are far rarer: hundreds of oysters or mussels must be opened to find even one. Because the two can look alike, labs tell them apart with X-ray imaging of the pearl's inner structure. **Key facts:** - In the United States, the word "pearl" on its own means a natural pearl. A cultured pearl must be called "cultured" or "cultivated". [1] - Hundreds of pearl oysters or mussels must be opened to find even one natural pearl. [2] - Cultured pearls became commercially important in the 1920s, at about the time natural pearl production began to decline. [3] - On an X-ray, a natural pearl shows no bead or curved cavity at its center, and a uniform, onion-like structure. [2] - GIA and SSEF weigh loose natural pearls in carats and grains, where 1 grain is 0.25 carat, and loose cultured pearls in carats only. [4, 5] - In 2018, Marie Antoinette's natural pearl and diamond pendant sold for CHF 36,427,000, a record for a natural pearl. [6] [Natural pearls](https://learnaboutpearls.com/glossary/#natural-pearl) and [cultured pearls](https://learnaboutpearls.com/glossary/#cultured-pearl) are grown the same way, by a living [mollusk](https://learnaboutpearls.com/glossary/#mollusk) laying down layers of [nacre](https://learnaboutpearls.com/glossary/#nacre). The difference is how the pearl starts. The table sums up the main differences. | | Natural pearl | Cultured pearl | | --------------------- | --------------------------------------------- | ------------------------------------------------------------------------------- | | How it starts | By accident, with no human help [7] | A person implants a bead or tissue [7] | | Its pearl sac | Formed naturally [8] | Started by human intervention [8] | | Inside, on an X-ray | No bead; a uniform, onion-like structure [2] | A bead under the nacre or, without one, an organic-rich center or void [9, 10] | | How rare | Hundreds of mollusks opened to find one [2] | Farmed in more than 30 countries [2] | | US name | “Pearl” or “natural pearl” [1, 8] | Must say “cultured” or “cultivated” [1] | | Weight on lab reports | Carats and grains [5] | Carats [5] | ## How natural and cultured pearls form A natural pearl forms in the body, or the [mantle](https://learnaboutpearls.com/glossary/#mantle) tissue, of certain mollusks, usually around a microscopic irritant, and always without human help of any kind. [7] A predator, a parasite or a lodged particle can move shell-making cells into the mollusk’s body, where they form a [pearl sac](https://learnaboutpearls.com/glossary/#pearl-sac) and keep making nacre. [2] A cultured pearl needs people to start it. A technician takes mantle tissue from a donor mollusk and inserts it into a host, either with a [shell bead](https://learnaboutpearls.com/glossary/#bead) in the [gonad](https://learnaboutpearls.com/glossary/#gonad) or as pieces of tissue alone in the mantle. The tissue forms a sac and coats the bead or tissue with nacre. [7] CIBJO defines cultured pearls as pearls formed inside living mollusks, in a cultured pearl sac, with human intervention. [8] The page [how pearls form](https://learnaboutpearls.com/basics/how-pearls-form/) explains both processes. ## How rare natural pearls are Natural pearls are rare. Hundreds of [pearl oysters](https://learnaboutpearls.com/glossary/#pearl-oyster) or mussels must be gathered and opened to find even one, and perfectly spherical natural pearls are extremely rare and highly valuable. For centuries this was the only way to get pearls. [2] The trade was once large. From 1850 to 1930, the Persian Gulf supplied perhaps 70–80% of the world’s natural pearls. [11] Cultured pearls became commercially important in the 1920s, at about the time natural pearl production began to decline. [3] The page [who invented cultured pearls](https://learnaboutpearls.com/history/cultured-pearl-revolution/) tells how that happened. Natural pearls can still set records: in 2018, Marie Antoinette’s 18th-century natural pearl and diamond pendant sold for CHF 36,427,000. [6] The page [famous pearls](https://learnaboutpearls.com/history/famous-pearls/) has more such stories. ## How labs tell natural and cultured pearls apart Natural and cultured pearls can look the same, so labs look inside them. The first gem testing laboratories, starting with London’s in 1925, first focused on telling them apart, and [X-ray radiography](https://learnaboutpearls.com/glossary/#x-radiography) remains an essential method for the job. [9] A natural pearl shows no bead or curved cavity at its center, and a uniform, onion-like structure. [2] Natural pearl - Formed with no human help - Even, onion-like layers to the center Cultured with a bead - A person implants a shell bead - The bead shows under the nacre Cultured without a bead - Started with tissue alone - An organic-rich center or a void - The hard cases for labs What labs look for inside: a natural pearl and two cultured pearls, cut in half. Drawn for Learn About Pearls; not to scale. **Text version of this diagram** Three pearls cut in half. The natural pearl has even, onion-like layers all the way to its center, and no bead. The pearl cultured with a bead has a large shell bead in the middle, with layers of nacre around it. The pearl cultured without a bead has layers of nacre around an organic-rich center or a small void, and its inside can look much like a natural pearl’s. Pearls grown without a bead are the hard cases. [Non-bead cultured pearls](https://learnaboutpearls.com/glossary/#non-beaded-cultured-pearl), often sold as [keshi](https://learnaboutpearls.com/glossary/#keshi), can have internal features much like those of natural pearls. [12] In 2010, SSEF warned that beadless cultured pearls, some sold with reports calling them natural, were entering the natural pearl trade. [13] ## How natural and cultured pearls are named In the United States, the unqualified word “pearl” may only be used for a natural pearl, one whose formation was in no way caused or induced by humans. A cultured pearl must be called “cultured” or “cultivated”, in letters as clear as the word “pearl”. [1] CIBJO’s standards say the same, and recommend labeling natural pearls as “natural pearls”. [8] Labs record the difference in weight too. GIA and SSEF weigh loose natural pearls in [carats](https://learnaboutpearls.com/glossary/#carat) and in [grains](https://learnaboutpearls.com/glossary/#pearl-grain), where 1 grain is 0.25 carat, and loose cultured pearls in carats only. [4, 5] ## Choosing between natural and cultured pearls Choose natural pearls if you want a rarity with a long history, and buy them only with a recent report from a gem laboratory that states they are natural. [5] Choose cultured pearls if you want a wide choice of types, sizes and colors. The [pearl types](https://learnaboutpearls.com/types/) section describes each one. ## Questions people ask ### Is a cultured pearl a fake pearl? No. A cultured pearl is grown by a living mollusk, which coats the implanted bead or tissue with nacre, while an imitation pearl is manufactured. A cultured pearl simply isn't a natural pearl, so it must be described as cultured. [1, 7] ### Are natural pearls more valuable than cultured pearls? Natural pearls are much rarer, and perfectly round ones are extremely rare and highly valuable. Within each kind, value still depends on size, shape, color, luster, surface, nacre and matching. [2, 14] ### How can I tell if my pearls are natural? Only a gem laboratory can confirm it, mainly with X-ray imaging of the pearl's inner structure. Reports from labs such as GIA and SSEF state whether a pearl is natural or cultured. [4, 5, 9] ### Are keshi pearls natural? No. Keshi are cultured pearls that grow without a bead as a by-product of pearl farming, though some look much like natural pearls inside and out. CIBJO says the word keshi should always be qualified as natural or cultured. [8, 12] ## References 1. U.S. Federal Trade Commission (Electronic Code of Federal Regulations). 16 CFR Part 23, Guides for the Jewelry, Precious Metals, and Pewter Industries. [Source](https://www.ecfr.gov/current/title-16/chapter-I/subchapter-B/part-23) · [Archived copy](https://web.archive.org/web/20260907072405/https://www.ecfr.gov/current/title-16/chapter-I/subchapter-B/part-23) 2. Changbo Zhu, Paul C. Southgate and Ting Li (2019). Production of Pearls. [Source](https://link.springer.com/chapter/10.1007/978-3-319-96776-9_5) · DOI [10.1007/978-3-319-96776-9_5](https://doi.org/10.1007/978-3-319-96776-9_5) · [Archived copy](https://web.archive.org/web/20240129152149/https://link.springer.com/chapter/10.1007/978-3-319-96776-9_5) 3. Gemological Institute of America (GIA), Gem Encyclopedia. Pearl History and Lore. [Source](https://www.gia.edu/pearl-history-lore) · [Archived copy](https://web.archive.org/web/20260612145202/https://www.gia.edu/pearl-history-lore) 4. 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) 5. Swiss Gemmological Institute SSEF. Pearls (SSEF reports). [Source](https://www.ssef.ch/reports/pearls/) · [Archived copy](https://web.archive.org/web/20260611191437/https://www.ssef.ch/reports/pearls/) 6. Sotheby's (2018). Marie Antoinette's Pearls Break Auction Records in Geneva. [Source](https://www.sothebys.com/en/articles/marie-antoinettes-pearls-break-auction-records-in-geneva) · [Archived copy](https://web.archive.org/web/20260410204948/https://www.sothebys.com/en/articles/marie-antoinettes-pearls-break-auction-records-in-geneva) 7. Gemological Institute of America (GIA), Gem Encyclopedia. Pearl Description. [Source](https://www.gia.edu/pearl-description) · [Archived copy](https://web.archive.org/web/20261017085317/https://www.gia.edu/pearl-description) 8. CIBJO, The World Jewellery Confederation, Pearl Commission (2026). The CIBJO Pearl Book (Pearl Blue Book) 2026. [Source](https://cibjo.org/wp-content/uploads/2026/10/Pearl-Blue-Book-2026-.pdf) · [Archived copy](https://web.archive.org/web/20261025235254/https://cibjo.org/wp-content/uploads/2026/10/Pearl-Blue-Book-2026-.pdf) 9. Chunhui Zhou and W. Henry Towbin (2024). Applications of X-Ray Radiography and X-Ray Computed Microtomography in Gemology. [Source](https://www.gia.edu/gems-gemology/winter-2024-x-ray-imaging) · DOI [10.5741/GEMS.60.4.582](https://doi.org/10.5741/GEMS.60.4.582) · [Archived copy](https://web.archive.org/web/20260313113455/https://www.gia.edu/gems-gemology/winter-2024-x-ray-imaging) 10. Artitaya Homkrajae, Nanthaporn Nilpetploy, Areeya Manustrong, Nicholas Sturman, Kwanreun Lawanwong and Promlikit Kessrapong (2021). Internal Structures of Known Pinctada maxima Pearls: Cultured Pearls from Operated Marine Mollusks. [Source](https://www.gia.edu/gems-gemology/fall-2021-internal-structures-pinctada-maxima-pearls) · DOI [10.5741/GEMS.57.3.186](https://doi.org/10.5741/GEMS.57.3.186) · [Archived copy](https://web.archive.org/web/20260420034834/https://www.gia.edu/gems-gemology/fall-2021-internal-structures-pinctada-maxima-pearls) 11. GIA staff (2025). Converge 2025 Speaker Presentations. [Source](https://www.gia.edu/gems-gemology/winter-2025-gemnews-converge-speakers) · [Archived copy](https://web.archive.org/web/20261025235910/https://www.gia.edu/gems-gemology/winter-2025-gemnews-converge-speakers) 12. Nishka Vaz, Abeer Al-Alawi and Anukul Belanke (2026). Diverse Range of Organic-Rich Cores in South Sea Non-Bead Cultured "Keshi" Pearls. [Source](https://www.gia.edu/gems-gemology/spring-2026-organic-rich-cores-in-south-sea-keshi-pearls) · DOI [10.5741/GEMS.62.1.26](https://doi.org/10.5741/GEMS.62.1.26) · [Archived copy](https://web.archive.org/web/20261025235759/https://www.gia.edu/gems-gemology/spring-2026-organic-rich-cores-in-south-sea-keshi-pearls) 13. Michael S. Krzemnicki (2010). Trade Alert: "Keshi" cultured pearls are entering the natural pearl trade. [Source](https://www.ssef.ch/wp-content/uploads/2017/12/newsletter_pearl_2010May-1.pdf) · [Archived copy](https://web.archive.org/web/20261026000024/https://www.ssef.ch/wp-content/uploads/2017/12/newsletter_pearl_2010May-1.pdf) 14. Gemological Institute of America (GIA), Gem Encyclopedia. Pearl Quality Factors. [Source](https://www.gia.edu/pearl-quality-factor) · [Archived copy](https://web.archive.org/web/20261016075647/https://www.gia.edu/pearl-quality-factor) **Written by:** Learn About Pearls editors **Fact-checked:** Learn About Pearls editors, November 1, 2026 **Reviewed by:** Simon, November 1, 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). _Natural vs Cultured Pearls: What's the Difference?_ Learn About Pearls. https://learnaboutpearls.com/compare/natural-vs-cultured-pearls/ **MLA:** “Natural vs Cultured Pearls: What's the Difference?” _Learn About Pearls_, Unique Pearl, November 4, 2026, learnaboutpearls.com/compare/natural-vs-cultured-pearls/. **Chicago:** Learn About Pearls editors. “Natural vs Cultured Pearls: What's the Difference?” Learn About Pearls. Unique Pearl. Last modified November 4, 2026. https://learnaboutpearls.com/compare/natural-vs-cultured-pearls/. **BibTeX:** `@misc{lap-compare-natural-vs-cultured-pearls, title = {Natural vs Cultured Pearls: What's the Difference?}, author = {{Learn About Pearls editors}}, year = {2026}, howpublished = {\url{https://learnaboutpearls.com/compare/natural-vs-cultured-pearls/}}, 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 - [Natural pearls](https://learnaboutpearls.com/natural-pearls/): Pearls that formed with no human help, why they are rare, and how labs confirm them. - [How pearls form](https://learnaboutpearls.com/basics/how-pearls-form/): How natural and cultured pearls grow inside a mollusk, layer by layer. - [Saltwater vs freshwater](https://learnaboutpearls.com/compare/saltwater-vs-freshwater-pearls/): How pearls from saltwater oysters differ from pearls grown in freshwater mussels.