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  • Writer's pictureKatrine Høilund Holmgaard

All you need to know about freshwater pearls

Updated: Aug 17, 2023

All you need to know about freshwater pearls

Cultured freshwater pearls:

Freshwater pearls are pearls formed in freshwater mollusks, such as oysters and mussels. Freshwater pearls are generally smaller and more expensive than saltwater pearls, such as Akoya pearls, Tahitian cultured pearls, or pearls from Australia.

Cultured freshwater pearls have only been developed in the last few centuries. Over the centuries the technique of cultivating freshwater pearls has evolved. Today the vast majority of freshwater pearls you come across are cultured pearls. Cultured freshwater pearls are produced by inserting a nucleus into the oyster, which stimulates the formation of a pearl.

Cultured freshwater pearls have therefore become popular due to their affordability and availability, and are now often used in fashion accessories and jewelry.

How is the freshwater pearl produced?

Freshwater pearls are formed by a freshwater oyster. The pearl is created when the oyster protects itself from an irritant, such as a grain of sand or a piece of gravel, that has entered its shell. Then the oyster creates layers around the irritant to protect itself, and it’s the nacre that covers the irritant that forms the freshwater pearl.

Freshwater pearls come in a variety of colors. There are six different colors associated with freshwater pearls, it goes from pink to lavender. Most cultured freshwater pearls are naturally white or yellow, however, some pearls are pink, green, blue, salmon, gray and black, these are obtained by dyeing the pearls. Dyed pearls are generally more affordable than natural pearls of rare colors. It’s important to be aware that dyed pearls can lose their color over time or when they’re exposed to sunlight or chemicals. If you buy dyed freshwater pearls it’s important to properly take care of them to maintain their color.

How long does it take for a pearl to be produced?

It really depends…

First, the difference between cultured pearls and natural pearls is the layers of nacre. The cultured pearls have a thin layer of nacre whereas the natural pearls have layer upon layer of nacre.


1,5 - 4 mm freshwater pearls take 2 - 4 years to produce in the shell.

5 - 30 mm freshwater pearls take 4 - 10 years to produce in the shell.

But the growth rate of nacre (nacre: the oyster covering the object with a fluid, layer by layer) varies depending on the type of pearl. For Chinese freshwater pearls it grows around 5mm per year, for Akoya pearls it’s 0,3mm per year, for Tahitian and Australian South Sea pearls it’s 2mm per year.

How long does it take to form cultured pearls?

It takes at least 6 months for a pearl to form. However, pearls are generally left for at least a year to grow to a decent size. The pearls can be harvested as early as 6 months in, but the longer the pearls are cultivated, the bigger the chances of harvesting a large and high-quality pearl. Usually, the freshwater pearls are cultivated for 18-24 months before harvesting.

Akoya pearls are usually harvested after 1 year, 2 - 4 years for Tahitian and Australian South Sea pearls, and 2 - 7 years for Edison freshwater pearls.

Pearls grow at different rates, depending on the type of pearl and a few other factors. The Akoya pearl could grow up to 9 mm in 10 to 14 months in diameter, a Tahitian pearl will grow 10mm in 18-24 months, while the Australian South Sea pearl could reach 15mm in 2 - 3 years.

How rare is it to find a pearl in an oyster?

Natural pearls are very hard to find, only 1 in 10.000 wild oysters will have a pearl. Most pearls that you see in the world are cultured pearls created by farming.

Only 5 - 10% of pearls are of excellent quality, but pearl farmers cultivate pearls of various qualities and manage to sell them.

How much are pearls worth?

Typically, round freshwater pearl strands range from 50$ to 2000$, and a strand of Akoya pearls costs 300$ to 10.000$.

Wild vs Cultured pearls - Wild pearls are more expensive due to the fact that they are formed out of the water and have to be found by divers or fishermen. Natural pearls are very hard to find, only 1 in 10.000 wild oysters will have a pearl. Most pearls that you see in the world are cultured pearls created by farming.

Freshwater vs saltwater pearls - saltwater pearls are a bit more expensive. They are more difficult to produce because they can only produce 1 or 2 pearls at a time. Where on the other hand a freshwater mussel can grow up to 32 pearls per shell.


Freshwater pearls from China make up more than 90% of today's worldwide pearl market. Therefore we took a trip to China to see what the extraction of pearls from oysters looks like.

Here you can see the video:


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