Pearls are a beautiful and highly desired gemstone formed inside the shells of certain mollusks. The most coveted pearls are cultured or natural saltwater pearls that grow within pearl oysters. However, some have wondered whether freshwater mussels and clams can also produce pearls.
What Are Pearls?
Pearls are formed when an irritant, such as a parasite or piece of sand, gets inside the shell of certain mollusks, including oysters, mussels, and clams. To reduce irritation from the foreign object, the mollusk secretes a fluid called nacre to coat the irritant. Layer upon layer of nacre coats the irritant, eventually forming a pearl.
Nacre is composed of calcium carbonate crystals held together by conchiolin, an organic protein-based adhesive. It has an iridescent appearance and produces the coveted luminescence of pearls. Both freshwater and saltwater mollusks produce nacre and are capable of forming pearls.
Characteristics of Freshwater and Saltwater Pearls
While both freshwater and saltwater mollusks can make pearls, there are some notable differences between pearls formed in these two environments:
Source Mollusks
- Saltwater pearls form within marine oysters, primarily the Akoya, white-lipped, black-lipped, and South Sea oysters.
- Freshwater pearls grow within certain species of freshwater mussels and clams.
Size
- Saltwater pearls tend to be quite large, ranging from 5mm up to 20mm. South Sea pearls can reach sizes of 20mm.
- Freshwater pearls are generally quite small, ranging from 2mm to 11mm. Large freshwater pearls over 10mm are rare.
Color
- Saltwater pearls display a wider variety of natural colors including white, silver, cream, gold, pink, peach, black, and blue.
- Freshwater pearls are typically white and tend to have more simple natural coloration. However, they can also present in pastel pink, peach, lavender, and purple shades.
Shape
- Saltwater pearls tend to have symmetric rounded or teardrop shapes.
- Freshwater pearls come in wider variety of shapes including oval, leaf-shaped, stick-shaped, and irregular.
Luster
- Saltwater pearls possess extremely high luster and shine.
- Freshwater pearls tend to have slightly more muted and lower luster.
Value
- Saltwater pearls, especially South Sea pearls, are far more valuable than freshwater pearls.
- High quality freshwater pearls have modest value while lower quality ones can be quite inexpensive.
Cultured vs Natural Pearls
Most pearls sold today are cultured pearls. Culturing refers to a process where pearl farmers induce pearl formation by manually inserting an irritant into the mollusk. This speeds up pearl growth so farmers don’t have to wait years for naturally-occurring pearls to form.
Both saltwater and freshwater mollusks can be cultured to produce pearls. The culturing process allows for more control over pearl size, shape, and color. However, natural undisturbed pearl formation results in unique one-of-a-kind gems.
Natural Freshwater Pearls
Natural freshwater pearls form on their own when a small parasite or debris particle happens to lodge itself within the mussel or clam shell. These pearls are rare and highly valued for their uniqueness.
China used to be the main producer of natural freshwater pearls from their native pearl mussels. Most natural pearl production ceased when pearl culturing became dominant. However, a few American pearl farms are now focused on natural production from wild mussels.
Cultured Freshwater Pearls
Most freshwater pearls today are cultured pearls grown within large freshwater pearl farms. China currently dominates freshwater pearl production, with smaller operations in the US and Europe.
To culture freshwater pearls, small bits of mantle tissue from a donor mussel are inserted into the target mussel along with a spherical or shaped bead nucleus. The tissue grafts onto the receptor mussel, eventually coating the nucleus with nacre and producing a pearl.
With freshwater culturing, pearl farmers can control the pearl size, shape, color, and level of luster and orient. Cultured freshwater pearls tend to be inexpensive since the mussels can be propagated en masse within ponds on pearl farms. However, higher quality cultured pearls with bright luster, few blemishes, and good color still command higher prices.
Can Freshwater Pearls Rival Saltwater?
For much of history, natural saltwater pearls dominated the pearl trade. Only royalty, nobles, and the wealthy could afford the extremely high cost of these rare gems.
However, the advent of pearl culturing in the early 1900s disrupted the industry. By the 1950’s, Japanese Akoya pearl farming expanded saltwater pearl production. Then in the 1970’s and 80’s, freshwater pearl farming took off and flooded the market with affordable smaller pearls.
While saltwater pearls still retain the top status, prices have dropped as cultivated pearls increased supply. Larger high quality Akoya, South Sea, and Tahitian saltwater pearls remain valuable. But smaller and lower grade saltwater pearls have become comparable in cost to freshwater pearls.
Today, freshwater pearls offer an affordable alternative pearl option. But in terms of luster, orient, surface quality, and colors, they still can’t quite rival top saltwater pearls. The best of the best will always be found in the sea.
Unique Qualities of Freshwater Pearls
Although freshwater pearls generally can’t compete with the luster and quality of fine saltwater pearls, they have some unique characteristics that set them apart:
- Affordability – High quality freshwater pearls are available at modest prices, making them more accessible.
- Fashion Colors – Their white color takes readily to dyeing, producing fun and vibrant colored pearl jewelry.
- Versatile Shapes – Baroque and non-spherical shapes allow for one-of-a-kind designs.
- Mix & Match Stranding – The affordable cost means strands can contain pearls of different sizes, shapes, and colors.
- Classic to Contemporary Looks – Freshwater pearls work equally well in traditional or modern, funky jewelry styles.
While freshwater pearls may not rival fine saltwater pearls in quality, they have unique characteristics that make them a compelling jewelry option. Their diversity, affordability, and mixability add versatility to pearl jewelry design and wearing.
Conclusion
In summary, freshwater pearls can and do grow naturally within certain species of freshwater mussels and clams. Both natural freshwater pearls and cultured freshwater pearls are produced.
However, freshwater pearls generally cannot rival the size, colors, luster, and quality of the best saltwater pearls. But they are a more affordable pearl option with their own set of unique qualities and pearl jewelry design potential.
So next time you have a choice of pearl jewelry, consider the unique beauty and value freshwater pearls can offer alongside the classic elegance of fine saltwater pearls.