All about Pearls

What’s the difference between freshwater and saltwater cultured pearls?

October 29, 2006 on 9:59 pm | In Pearls, Jewelry |

Freshwater pearls are grown inside freshwater mollusks and saltwater cultured pearls are grown inside saltwater mollusks. Both saltwater pearls and freshwater pearls are real pearls–they are just grown in different mediums. They are both termed ‘cultured’ pearls because they have a human hand in their development. A so-called ‘natural’ pearl is the result of a random irritant getting caught inside a mussel (in the case of freshwater pearls) or oyster shell (in the case of saltwater pearls) and the irritant getting coated with its nacre (the material that pearls are made from) in order to deal with the source of the irritation. Jewelry-grade natural pearls are extremely rare and exceedingly expensive–most people are unlikely to encounter them. Fortunately, the process of culturing pearls–both saltwater and freshwater–has brought real pearls to a much wider market.

Culturing pearls, both saltwater and freshwater, involves an irritant being deliberately introduced into mollusks so that pearls will (hopefully) form. Because the freshwater mussel can produce many more pearls in its lifetime than its saltwater cousin, the oyster, freshwater pearls are typically less expensive than saltwater ones. However, unlike saltwater pearls, freshwater pearls are composed of nacre (the ‘pearl’ material) all the way through, while saltwater pearls are composed of many layers of nacre covering the small round bead that was the original irritant that the saltwater pearl was formed around. For freshwater pearls, the irritant that is introduced into the mussel is a piece of mussel tissue and it gets absorbed back into the mussel during the pearl-growing process, leaving a pearl made of solid nacre in its wake.

Which are better–freshwater or saltwater pearls? Saltwater pearls are certainly more expensive, due to their greater scarcity, and because they are created by seeding oysters with small, round beads onto which to secrete nacre, they tend to be rounder than freshwater pearls. However, as they are not solid nacre throughout, as freshwater pearls are, their nacre may eventually wear off after a great many years. In my opinion, there are a lot of beautiful freshwater pearls on the market that are very reasonably priced and that provide an excellent alternative to their more expensive saltwater cousins.

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