gems, ancient gems, glyptic, analytical technology, Mesolithic, Neolithic, Chalcolithic, Bronze Age

A microscopic examination of silicone impressions of the perforations of beads, seals tones, and amulets has produced a data base of characteristics that help to define what type of drill was used to make them. This article outlines the various types of drills that have been used from the Palaeolithic period to the present day, and notes what microscopic features characterize each one. Scanning electron micrographs illustrate the minute details that are revealed by the silicone impressions.