Instead of traditional precious gems, Cresta Bledsoe and Jacquie Aiche have turned to unconventional materials—well-preserved shark teeth—as centerpieces for their latest jewelry works, giving the fossils an extraordinary second life.

For decades, relatives of Bledsoe’s combed the shores of Ponte Vedra Beach on the northeast coast of Florida for fossilized shark teeth, eventually accumulating a vast collection that she now sets in recycled 18-karat gold and crafts into earrings, rings, necklaces, and bracel…