Diamonds are a girl's best friend, but in the Middle Stone Age shell beads were all the rage. Recent excavations by the University of Bergen at Blombos cave, on the coast of South Africa, have unearthed 41 delicate beads approximately 5mm across made from the tiny shells of an aquatic snail nassarius kraussianus. The beads have been deliberately pierced with a sharp stone point and show evidence of wear consistent with friction from some kind of cord or thong. Their manufacture has been scientifically dated to 75,000 years ago.