for The Legend of the Cape May Diamond by Trinka Hakes Noble and E.B. Lewis
For thousands of years, quartz fragments have traveled down the Delaware River (once called the Wehittck by the Lenape Indians), washing ashore near a place settled by the Dutch explorer Cornelius Jacobson Mey, where they are gathered as treasures and known as Cape May Diamonds. The stone that man can see through was so highly prized, it was never used for wampum, but became the sacred stone to seal the bonds of loyalty and friendship.
Publisher description retrieved from Google Books.