Freshwater pearls are created naturally in response to a threatening and/or irritating entity randomly entering a mussel’s shell, after which the intruder is coated with layers of organic matter to seal it off from the vulnerable, soft-bodied organism. This process occurs only rarely in nature, and randomly-encountered natural pearls have therefore always been extremely scarce. In fact, the Roman historian Suetonius claimed that Scotland’s river pearls were a primary motivation behind Julius Caesar’s ultimately-unsuccessful invasion of Britain in 55 BC.

However, a “culturing” process was eventually developed whereby the above chain of events could be initiated via human intervention, and the vast-majority of today’s freshwater pearl farms are located within China’s remote, non-polluted lakes and rivers. With the low Chinese labor costs and large number of pearls that can be grown within a single mussel, cultured freshwater pearls tend to be far more affordable than their marine counterparts.