Freshwater Pearls: Origin, Sizes, Quality and Value

Freshwater cultured pearls are cultured pearls grown in freshwater mussels. They are the most commonly produced pearls, and among the most popular, for their range of sizes, shapes and colors and their lower prices.⁵

Where freshwater pearls come from#

Freshwater pearls grow in mussels, not oysters. In China most come from the triangle shell mussel, Hyriopsis cumingii, with Hyriopsis schlegelii and Cristaria plicata also used.² GIA describes pearls from H. cumingii and its hybrids,³ while CIBJO’s 2025 guide reports that hybrid mussels are no longer used in China.²

Japan once had its own freshwater pearl industry. Hyriopsis schlegelii was used in Lake Biwa and Lake Kasumigaura from the early 1900s until before the 1990s.² Japan’s freshwater pearl output peaked at 6.3 tons in 1980 and fell to 214 kg by 1998, after water contamination and high mussel mortality.⁸ Chinese researchers later imported H. schlegelii from Japan and crossbred it with the native H. cumingii.⁴

Chinese freshwater cultured pearls first appeared on the market in the late 1960s and early 1970s.⁸ Japan imported only 600 grams of them in 1971, but over 49 tons in 1984, mostly for export to other countries.⁸

Where freshwater pearls are farmed#

China is the leading source of freshwater cultured pearls.⁵ Most are grown in Zhejiang, Hubei, Hunan, Anhui, Jiangsu and Jiangxi provinces, in lakes and ponds.²

The volume is enormous. From 2005 to 2014, China produced an average of 3,540 tonnes of pearls a year, 99.5% of them freshwater, and over 98% of the world’s cultured pearl output by weight.⁹ Because freshwater pearls sell for much less than saltwater pearls, that output made up only about 5% of the world’s pearl value.⁹ CIBJO’s current estimate is 1,000 to 1,500 tonnes a year, or 800 million to 1 billion pearls, with a retail value of about US$3 billion in 2024.²

Farming at that scale has costs. CIBJO reports that intensive farming, which adds phosphates to the water to feed the mussels, is causing environmental problems, including severe pollution of water tables in some areas of China.²

How freshwater pearls are grown#

Most freshwater pearls are grown without a bead. A technician implants pieces of mantle tissue into the mussel’s mantle, up to 20 in each of its two mantle lobes,⁹ and nacre forms around each piece.⁵ Almost all freshwater pearls are grown this way.⁶

Freshwater mussels grow faster than pearl oysters and are ready for grafting within a year.⁹ A mussel usually produces 30 to 40 non-beaded pearls at a time, but only one or two when a large bead is used.² Culture usually takes 1 to 5 years, depending on the method and the mussel,⁹ and the dataset gives a growing time of 1–5 years (depending on the culture method and mussel)⁹.

Time in the water trades against size. In 2001, GIA’s journal described growers who grafted mussels about two and a half years old and harvested two to three years later, and others who grafted younger mussels and grew the pearls for four to six years to get larger pearls.⁸

Some freshwater pearls are now grown around a shell bead, the method used for Akoya. These are often near-round to round, bright white and very lustrous.³ Trade names for bead-cultured freshwater pearls include Coin, Fireball, Edison, Ming and Soufflé; a soufflé pearl’s core is removed after drilling, which leaves it hollow.²

Freshwater sizes, shapes and colors#

Freshwater cultured pearls are typically 3–15 mm, within a range of 3–25 mm². GIA notes that the smaller pearls are usually non-bead cultured, while the larger ones are often bead-cultured.⁷

CIBJO lists freshwater shapes as round, near-round, oval, coin and baroque². In 2001, GIA described Chinese freshwater pearls in shapes from extreme baroque to perfect round, a big change from the bulbous oval “potato” pearls common in earlier years.⁸

Freshwater pearls come in white, cream, pink, peach, orange, lavender and purple². CIBJO adds that darker natural colors often show a metallic luster, and that yellow and green are rare.²

Quality factors for freshwater pearls#

Freshwater cultured pearls are judged on the same factors as saltwater pearls. CIBJO’s guide, following a 2023 standard, lists six: color, size, shape, luster, surface condition and nacre thickness, with matching added for jewelry with several pearls.²

Shape weighs heavily. Round is the most difficult shape to culture and the rarest cultured pearl shape, and when other factors are equal it is generally worth the most.¹² A GIA report also states whether pearls grew in freshwater or saltwater.³

What affects the price of freshwater pearls#

GIA calls freshwater cultured pearls the most affordable pearl type, and says Akoya cost more than freshwater pearls of similar size and quality, in part because they are rarer and cost more to culture.³ Freshwater production is so large that lustrous examples are affordable, in part because each mussel produces dozens of pearls.¹³

Within freshwater pearls, the usual factors set the price. When other factors are equal, larger pearls are rarer and more valuable.¹²

Identification, treatments and imitations#

Labs separate freshwater from saltwater pearls by chemistry. Freshwater pearls contain more manganese and barium and less strontium, and they glow more strongly under X-rays, because X-ray luminescence brightens with manganese.^{11 14}

Bead-cultured freshwater pearls can look like Akoya and are sometimes sold as “freshwater Akoya”, a name GIA calls incorrect. A GIA report states the environment a pearl grew in.³

Treatments are common. CIBJO says it is common for Chinese freshwater pearls to be bleached and otherwise treated.² GIA reports that optical brightening is routinely applied to untreated, naturally colored freshwater cultured pearls after harvest, and that the most common color treatments are dyeing and irradiation.¹⁰

Imitations are a separate matter. In the United States an imitation pearl must be called “imitation”, “artificial” or “simulated” whenever the word “pearl” is used.¹⁵

Caring for freshwater pearls#

Freshwater cultured pearls need the same care as other pearls. Put them on after perfume and cosmetics,¹³ wipe them with a soft cloth dampened in clean water after wearing, and keep them away from acids, solvents, heat and ultrasonic cleaners. Some color-treated pearls can fade or revert to their original color under strong light.¹ The care section has the full routine.