The first post in this series took a look at a natural pearl and how the process involved in its creation leads to the emergence of a beautiful work of nature. I explored the different parts of the oyster and how a foreign substance contributes to the creation of the pearl. While this natural process can produce a beautiful pearl, it is also convenient to have more at a jeweller’s disposal than what nature can produce.
As a result, we have developed the freshwater cultured pearls. A freshwater cultured pearl is one that comes from a freshwater mussel. In many markets, such pearls must be legally referred to as freshwater cultured pearls by governing bodies of commerce.
While such pearls have been produced in the United States and Japan, the production is now almost exclusive to China. This process is fascinating as it does not rely on a foreign substance to find its way into the mussel, but instead on technicians performing a grafting process on the mussel.
The grafting process requires a technician to make a small incision on the upper valve of the mussel and insert a piece of tissue from a donor mussel. This tissue is then considered to be the foreign substance by the mussel and it will begin the natural process of coating the tissue with a protective material.
While the cockscomb pearl mussel was once preferred in the Chinese cultured pearl industry for its ability to produce as many as 50 pearls, the low quality of the pearls earned them the name, “rice krispy pearls”. The favored mussel is now the triangle shell as the pearl quality is superior, even if the total quantity is fewer.
Freshwater cultured pearls are delivered to a first-stage after they are harvested from the shells of the mussels. This first stop is generally where the pearls will be cleaned and sorted according to size and shape. Once sorted, the pearls go through a standard treatment of maeshori, which includes immersion in a warm and cold chemical solution, bleach, drill and polish. (If a pearl exhibits strong coloration, it will only go through maeshori.)
When the pearls have completed the standard sorting process, they are then matched with like-sized and shaped pearls onto temporary strands. These strands are then matched again into hanks, which is a group of strands comprised of five to 10 temporary strands. At this point, the pearls are considered to be ready for the wholesale market.
Freshwater cultured pearls do differ from saltwater pearls in that they are typically not as round as saltwater pearls and do not have the same sharp luster and shine. Freshwater cultured pearls do, however, appear in a wide variety of natural colors and shapes and are more durable than saltwater pearls. They also make a nice contribution to any jewellery collection where a budget must be adhered to as they typically cost less, because of the farming aspect, than the saltwater variety.
My overall preference in the choice of pearl depends entirely on the jewelry setting and the purpose of wear. If you are making a fashion statement, freshwater cultured pearls are a logical choice. If you want to keep with tradition and display an authentic pearl, nothing compares with a saltwater pearl.
Join me next time as I take a closer look at the unique pearls found in the South Sea.