Mollusks produce pearls by coating a trapped irritant in layers of nacre. Finding a natural pearl can require opening over a thousand mollusks, contributing to their high value and historical association with royalty, wealth, and status. Pearls have been collected by people across the world for thousands of years. Prized for their beauty and imbued with a range of symbolic meanings, pearls reached the height of their value in the 16th century. Large quantities of pearls were taken from colonies in the New World and imported from Asia to demonstrate the colonial might of rulers such as Queen Isabella and King Ferdinand of Spain or Queen Elizabeth I of England. Despite these new sources, and the manufacture of glass imitations in Venice beginning in the 16th century, the rarity of natural pearls maintained their high monetary value and exclusivity through the 17th century and beyond.
Since the 1920s, cultured pearls produced by intentionally introducing a nucleus into farmed mollusks have become common and made pearls widely accessible. With the exception of a few items dropped by modern visitors, the pearls in the Jamestown collection are naturally occurring freshwater pearls. Freshwater pearls are formed more quickly than saltwater pearls and tend to be smaller. They are also more likely to be cream-colored or off white, grey, or even pink or purple in color rather than white. Grey is the most common color among the drilled pearls in the Jamestown assemblage. Freshwater pearls and natural pearls are both typically imperfectly shaped, rather than truly spherical. Modern cultured pearls are often formed around a spherical bead, giving them a distinctly perfect shape, providing one of several easy ways to distinguish between the historical artifacts and modern intrusions.
Freshwater pearls often come from mussels, but can also develop inside oysters, which are plentiful in the brackish water of the James River. Thousands of mussel shell (Geukensia demissa) beads crafted by native women and piles of oyster shells (Crassostrea virginica) have been excavated here at Jamestown, attesting to the local abundance of these species and their use by both the colonists and Native peoples. Pearls would have been of value to both groups, making it difficult to determine who collected the pearls, drilled the holes to string them, and ultimately wore them. About half of the roughly 40 pearls found at Jamestown were discovered during excavations in 2009 in the John Smith Well, which dates from 1608 to 1610, and several more were found in the West Bulwark Trench, another very early context. This indicates that pearls were worn and likely traded during the earliest years of the Fort Period.