Although we know that the most genuine pearls are the natural pearls, yet we also know that they are very difficult to find. As a result they are also exorbitantly priced. It was thus not possible to meet the expanding demands for pearls in the market. Hence pearls began to be cultured and new and innovative ways were developed to produce harvests of a variety of pearls of different shapes sizes and colors. Different species of oysters and mussels were tested to get pearls of different colors and shapes and good luster. Over a period of time, we find that almost the entire market of pearls is flooded with cultured pearls. A great irony in the history of pearls is that the least expensive cultured pearl product in the market today rivals the quality of the most expensive natural pearls ever found. The price-value anomaly is obvious to consumers as they hasten to buy Chinese freshwater bargains.
Cultured both in saltwater and freshwater these pearls dominate pearl industry. Indeed, pearls from freshwater mussels lie at the center of the liveliest activity in pearling today. The process of formation of the natural freshwater pearls occur in mussels is similar to that of saltwater pearls in oysters. To culture pearls from freshwater mussels or oysters in saltwater, workers slightly open their shells, cut small slits into the mantle tissue inside both shells, and insert small pieces of live mantle tissue from another mussel or some core into those slits. In freshwater mussels that insertion alone is sufficient to start nacre production. Most cultured freshwater pearls are composed entirely of nacre, just like their natural freshwater and natural saltwater counterparts. Beautiful lustrous pearls can be harvested in this way and sold at affordable prices. Cultured freshwater pearls and saltwater pearls thus help us to meet the ever growing demand for pearls among consumers.
These cultured pearls could come in many colors. Usually they are white, sometimes with a creamy or pinkish tinge, but may be tinted with yellow, green, blue, brown, purple, or black. Black pearls, frequently referred to as Black Tahitian Pearls are highly valued because of their rarity; the culturing process for them dictates a smaller volume output and can never be mass produced. This is due to bad health and/or non-survival of the process, rejection of the nucleus (the small object such as a tiny grain of sand inserted by the pearl farmer), and their sensitivity to changing climatic and ocean conditions.
Japan was the pioneer in culturing freshwater pearls. The Biwa pearls though no longer in productions are remembered to this day. China came next as the resources came to an end in Japan. Developing the technology in gradual stages China today is a major supplier of freshwater pearls.
Some freshwater pearls are produced in America too but these are of interest only for some of the weird shapes available, like pearls that look like wings.