Quahog shells were used by Native Americans to make a kind of shell bead called wampum. These beads were made from the dark purple portion of the quahog (hardshell clam) by skilled artisans. The white beads were made from another type of shell. The artisans used specialized stone tools to shape and smooth the small beads and to drill holes in the finished pieces. They would string the beads and wove the strings into belts, ornaments, and necklaces. Traditionally used as a social exchange item to solidify political alliances and maintain relationships between friends and relatives, wampum became a medium of exchange, a kind of currency, during the beaver trade with Europeans in the 1600s.