Natural Science in Archaeology

92 5 Gemstones, Seal Stones, and Ceremonial Stones
of this mineral during antiquity, lapis is found widely throughout the Old World
(Herrmann 1968). The word lapis comes from the Latin for stone.
Throughout history, gemstones have been cut or shaped in order to enhance their
beauty. In antiquity this often consisted of simply smoothing and rounding rough
edges. However, ancient examples of carving can also be found. Even extremely
hard substances such as rock crystal (quartz) were carved into elaborate objects
including jewelry, sculptures, and vessels. The Babylonians carved seals into cylinder-shaped
gems to use as ornaments and to make impressions in soft wax or clay
for personal identification (Whitlock 1934). The Romans continued this practice by
carving seals into ring stones (Zienkiewicz 1987).
The most popular materials for seal manufacture were quartz minerals (Fig. 5.1).
Although quartz was more difficult to carve than softer stones, the resulting product
was quite durable. Ancient craftsmen must have understood that a very hard material,
such as emery (impure corundum, usually containing magnetite), was required
to shape or engrave quartz (Collon 1989).
It should be noted that the enhancement of optical properties in gems was not
well understood until relatively recently. Ancient craftsmen often polished gems
or hollowed out the back in order to encourage the transmission of light through
the stone (Osborne 1912), but faceting was not developed until the medieval era.
Fig. 5.1 Quartz seal from Tel
Michal, Israel