gems, early lapidary, diamond, diamond drilling, Sri Lanka, India

Evidence is presented that quartz beads excavated in Mantai, Sri Lanka (ca. A.D. 700–1000, by Carswell), and in Arikamedu, Southeast India (ca. 250 B.C.–A.D. 300), were drilled using natural diamond splinters. This conclusion is supported by comparing the drilling patterns found in these ancient beads with those observed in quartz beads from modern-day Cambay, India, where diamond drills are still used. The researchers also successfully replicated the same drilling pattern experimentally. All beads were examined using silicone impressions and scanning electron microscopy. This represents the first reported evidence for the use of diamond drills in the ancient world. Further support is offered for the idea that Roman gem engravers employed Indian diamonds, based in part on textual references from the Periplus, Pliny the Elder, Solinus, and the Arthra-Sastra.