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Published online by Cambridge University Press: 22 February 2011
The major events that promoted gemstone jewelry production in ancient Rome included: the separation of gold from silver, the expansion of land trade routes to the east, and presentations of treasure during Roman triumphs that popularized eastern jewelry. In this paper a fourth event is studied, namely the development of the sea trade to India and Sri Lanka that made possible the importation of sapphires and diamond technology. Classical references were reviewed, methods of identifying Sri Lankan sapphires were explored, and experimental studies were undertaken to test various bow drills, abrasives, and methods of securing stones and abrasive onto solid surfaces. From these studies it is concluded that (1) opaque dark blue sapphires were imported from central India around the first or second century A.D. and pale blue transparent stones from Sri Lanka by the fourth century A.D., (2) with the importation of sapphires, industrial diamonds and lac technology was also brought to the west, and (3) a wide variety of bow drills were probably employed, however, for hard stones, the horizontal bow driven lathe was probably preferred because of the relative ease with which stones could be worked against it.