From The Bead Scoop Vol. I Issue 3, Dec 2007
Where Do Freshwater pearls come from?
Freshwater pearls are simply pearls formed by freshwater mussels rather than saltwater oysters. Both mollusks produce pearls in a similar way: an irritant (the proverbial “grain of sand”) enters a mollusk’s shell and cannot be expelled. The mollusk then coats the intruder with the same secretion it uses for shell production, a hard, smooth substance called nacre. Over time, more layers of nacre build up and the pearl grows in size. The nacre will become thicker the longer it is left to grow, adding to the pearl’s luster, durability and value.
Nowadays wild or natural pearls are very hard to find. Most pearls on the market are cultured or farmed whether from saltwater oysters or freshwater mussels. Typically, cultured saltwater pearls have had a small round piece of mother-of-pearl inserted into the shell to initiate growth of a nice, round pearl. Cultured freshwater pearls, however, are often non-nucleated; that is, the insertion is just a piece of tissue, not a sizable object. This means that many freshwater pearls are composed entirely of nacre and offer fabulous color and luster, albeit in an off-round shape.
In the 1930s, commercial production of freshwater pearls started in Lake Biwa, near Kyoto, Japan. These all-nacre pearls offered excellent luster and color unseen in many cultured saltwater pearls. Production in Lake Biwa has since declined (although the name “Biwa” is still used indiscriminately) and most freshwater pearl production is taking place in China. The quality and variety of Chinese productions has improved greatly over the years and prices remain markedly low.
Since the 1990s, China has been breaking the boundaries of pearl production, introducing new shapes, colors and culturing methods with quality rivaling the original Biwa pearl or the round Japanese Akoya pearl. Farmers are inserting unusual nucleus material into mussels creating great shapes; improving upon color-enhancement methods like bleaching, dyeing and radiation; even faceting pearls! The end result is an ever-growing selection of pearls for new designs and beading inspiration!
Related: How to Choose Pearls June 2010