WHAT MAKES THEM DIFFERENT?
First, freshwater pearls are grown in lakes and ponds in mainland China and saltwater pearls are grown in the Sea of Japan. Saltwater pearls are produced by oysters; mussels produce freshwater pearls. The mussels that grow freshwater pearls are extremely durable and are capable of producing pearls in much harsher conditions than saltwater oysters. Although there are many differences between these varieties nothing may separate them more than the fact that one freshwater mussel can produce up to 40 pearls in just one harvest versus saltwater oysters only produce one.