Yup. Diving for them in the Tennessee and Ohio Rivers.  You can even take a tour of a fresh water pearl farm set up with the much coveted indigenous American mussel. Globally for centuries, many a diver met a gruesome, horrifying death while diving for pearls. Many Japanese women.

Japanese Pearl Diver

Wiki exposes the hard truth in this risky business

In order to find enough pearl oysters, free-divers were often forced to descend to depths of over 100 feet on a single breath, exposing them to the dangers of hostile creatures, waves, and drowning, often as a result of shallow water blackout on resurfacing.

In Asia…divers had to go 40 feet (12 meters) or even up to 125 feet (40 meters) deep to find enough pearl oysters, and these deep dives were extremely hazardous to the divers. In the 19th century, divers in Asia had only very basic forms of technology to aid their survival at such depths.

This stuff has been going on for centuries. Remember reading how Spain pillaged the pearl industry back in the colonial days.

Tennessee River Pearls

In a similar manner as in Asia, Native Americans harvested freshwater pearls from lakes and rivers like the Ohio, Tennessee, and Mississippi, while others successfully retrieved marine pearls from the Caribbean and waters along the coasts of Central and South America.

In the time of colonial slavery in northern South America (off the northern coasts of modern Colombia and Venezuela), a unique occupation amongst slaves was that of a pearl diver. A diver’s career was often short-lived because the waters being searched were known to be shark-infested, resulting in frequent attacks on divers. However, a slave who discovered an extra-large pearl could sometimes purchase his freedom.

Nowadays, they really ramp up the cultured pearls with many ‘irritants’,  nucleaters producing abundant harvest for each mussel.  You have to see how huge these mussels are.  Some pearls are still just scavenged from the wild in these parts if this source can be believed

Pearl diving in the Ohio and Tennessee rivers of the United States still exists today. These pearls are called natural pearls, because they are created by nature alone, and are not cultivated by humans. Their shapes are uniquely baroque^{[citation needed]}. Fewer than 1% are found in the classic round shape. They are very rare and are considered collector’s items.

This source discusses the discovery of gorgeous silver pink pearls found in the Ohio River over a century ago.  It was like a gold rush.

Queen Pearl found in Jersey

A large portion of this collection of Ohio river pearls was exhibited in the American section of the Paris Exposition of 1889, and was awarded a gold medal. A pink pearl of eight grains was admired by all who saw it; by reflected light this had the color and translucency of a drop of molten silver.

Many of the pink Ohio river pearls found in the Little Miami and its tributaries were of the most beautiful rose-petal pink; pearls of this peculiar color have never been found in any other waters.