gems, ancient gemology, early gemology, ancient mineralogy, early trade, ancient lapidary, lapidary arts, diamond, diamond drills, India, Sri Lanka, Thailand, Greek, Roman, Pliny

The technological history of diamonds as tools in the ancient world is even more obscure than their use as gemstones. Experimental evidence from Arikamedu in southeast India, dating to around 250 B.C.–A.D. 300, represents the earliest known instance of diamond tool use. Archaeologist Mortimer Wheeler discovered a bead workshop at Arikamedu, along with compelling signs of Roman trade. It is very likely that the Romans learned to use diamond splinters as drills in Arikamedu. Pliny the Elder notes that diamond splinters “are much sought after by engravers of gems” (Natural History 37.15.61), and further Sanskrit and Roman literary sources support this. Though additional references are scarce, they help trace the continued use of diamonds as engraving tools through the Sassanian and Islamic periods following Rome’s decline. While evidence for the European Middle Ages is lacking, documentation reappears in 15th-century Europe. Today, diamonds continue to serve in modern industry and crafts, as well as in traditional settings like the beadmaking village of Cambay, India, where artisans still use diamond-hafted bow drills. Beads from Cambay, in fact, provided the initial clues that helped interpret this experimental evidence.