gems, engraved gems, garnet, agate, chalcedony, quartz, cameos, itaglios, turquoise, sard, onyx, coral, amethyst

The GCEM project (Garnets: Classical, Eastern and Medieval): This paper presents the initial findings of the GCEM project,designed to create a scientific database of garnet intaglios held in different departments in the British Museum. Of all the ancient stones used as seal stones, garnets are perhaps the most promising in terms of yielding a broad reference database.Unlike diamond, the corundum series (ruby, sapphire) and spinels which were used relatively rarely in antiquity, substantial numbers of garnets were used steadily over many centuries. And, unlike the inclusions in the quartz group whose various members are ubiquitous throughout antiquity, the distinctive inclusions within garnets, when compositionally identified, may in some cases be used to match a particular gemstone to a host rock.