What’s The Difference Between Freshwater Pearls and Saltwater Pearls?

What’s The Difference Between Freshwater Pearls and Saltwater Pearls?

Time for a little biology lesson! Well, sort of. We’d like to talk a little about our favourite gemstone, the one we use in our beautiful jewellery… the mighty pearl.

You all know (or perhaps a small number don’t) that pearls are an entirely natural gemstone, insofar as they are created inside an oyster or a mussel. But there are also cultured pearls which are also technically natural as they’re still grown inside molluscs… but are not classed as ‘natural pearls’. Some cultured pearls are grown in fresh water and some in saltwater. The freshwater pearls we use to make Glam Confidential jewellery are the closest to natural, wild pearls.

Confused? Don’t worry – here’s a handy guide that we put together to make it all clear!

Natural Pearls

natural pearls

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These are the most valuable pearls in the world as they are incredibly rare. They occur spontaneously in wild molluscs, apparently when tiny bits of bacteria enter their shell, or even when they are damaged in some way. The oyster then secretes a substance called nacre, which builds up in layers over time, to form the irridescent pearl we all know and love. In a natural, wild pearl, the composition is almost entirely nacre, except for the tiny bit of other matter in the very centre.

Natural pearls are rarely found these days – partly because they are not as widely sought since the improvements in cultured pearls. Most of the natural pearls on the market today are vintage or antique.

Cultured Pearls

Cultured Pearls

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These are pearls that are still produced by nature, but are essentially man-made. An irritant is introduced into a mollusc shell – either a tiny piece of shell itself or a spherical bead – and the same process begins inside. The cultured pearl is made of the same layers of nacre, but with a larger non-pearl body in the centre. They are indistinguishable from natural pearls from the outside, a process that was carefully perfected in the early 1900s by the Japanese, including the famed Mikimoto.

In the early days of pearl culturing, it was believed that only saltwater pearls could be made spherical – the freshwater ones came out as irregular seed shapes. But now freshwater pearls are arguably the finer of the two.

Saltwater Pearls

saltwater pearls

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Back in the early days of pearl culturing, Mikimoto’s lot had good success with saltwater pearls, but very little with freshwater ones. For some reason, they always came out shaped like irregular grains of rice and became synonymous with lower quality.

But the Japanese perfecting the perliculture technique, even if the first commercial crop of saltwater cultured pearls was not made until 1928. A labour of love, indeed! Saltwater cultured pearls are ‘beaded’, when a tiny polished sphere of mussel shell is inserted into another mussel or oyster, and used to kickstart the process.

Freshwater Pearls


After the many years of failture to produce round, freshwater pearls, WWII halted progress on the Japanese side, but the slack was picked up by the Chinese, who have utterly perfected the process. This is due to the fact that beads are not used to start the pearl formation, rather, a tiny piece of tissue that is virtually undetectable in the finished pearl.

They are almost 100% nacre and almost indistinguishable from natural pearls, even under X-ray – all the same lustre and quality. And, as a bonus, freshwater pearls are greener to make and free of the pollutants you can find in the oceans, too. That’s why we use these little pieces of beauty in our jewellery.

Of course… there’s one type of pearl we haven’t mentioned… the imitation pearl. But why have faux when you can have the real thing?

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