Natural Science in Archaeology

112 5 Gemstones, Seal Stones, and Ceremonial Stones
Large-grained calcite (i.e., “marble”) was also used worldwide in the manufacture
of seal stones, vessels, figurines, and small art objects. Marble is opaque and can
have almost any coloring depending on the presence and amounts of other constituents.
The ancient Egyptians obtained marble from the Eastern Desert. They used it
mainly for statues and decorative objects, but large marble bangles are known from
the Early Dynastic Period (Andrews 1991).
5.4.2 Fine-Grained
Calcite, CaCO 3 , The fine-grained varieties of calcite usually are referred to as limestone.
The appearance of limestone varies widely depending on the presence and
amounts of other minor constituents. Limestone occurs in various shades of white,
cream, yellow, buff, pink, gray and black. A black variety found in the Egyptian
Eastern Desert was carved into beads and pendants from the Badarian Period. Pink
limestone from the Western Desert was used for beads and amulets during the Old
Kingdom and Early Dynastic Period (Andrews 1991).
Aragonite, CaCO 3 , has a hardness of 3.5 and a density of 2.94.
Pearl. The chief mineral component of pearl is aragonite (CaCO 3 ). The name aragonite
is derived from Aragon, Spain. The color of pearls varies with the type of mollusk
species and its water environment. Pearls are characterized by their translucence and luster
with an intricate play of surface color. The iridescence is a result of the refraction of
light through many layers. Pearls can be found in white, yellowish-white, pinkish-white,
bluish-white, reddish, or blackish-gray. The name originates from Latin perma, a type
of shellfish. Mother-of-Pearl is a concretion formed by a mollusk as the bivalve mollusk’s
shell. The highest quality pearls are produced from the genus Pinctada.
Pearl-oysters and pearl-mussels are found on the Red Sea coast of Egypt, in
the Persian Gulf, and off the coast of Sri Lanka (Ceylon). Perhaps the earliest use
of pearl in Europe dates to the Paleolithic, when it was used with mussel shells as
jewelry. Although pearls have long been a valued gem, they generally were not used
in Egypt until Ptolemaic times (Lucas 1989). Pliny lists a number of sources for
margarites including the seas around India, Arabia, Sri Lanka, the Persian Gulf and
the Red Sea (N.H. 37.12, 14–17, 62; 9.106–123). In Southeast Asia, mother-of-pearl
was used widely as an inlay to decorate jewelry, boxes, weapons, and furniture.
Saltwater pearls were also harvested from the northwestern Pacific Ocean and the
waters around Japan. Pearls were highly prized on the Arabian Peninsula where
there was a highly developed pearl diving and trading industry. The general name
for the pearl in Arabic is lulu ( ), but this term was often qualified by an elaborate
nomenclature based on shape, size and color. In the Old World, pearls were
used medicinally and were made into beads or gemstones. Mother-of-pearl was
used in mosaics during the Roman Empire; the interior of Nero’s palace, Domus
Aurea in Rome, was inlaid with mother-of-pearl. This practice continued, as can
be seen in the famous Ravenna mosaics in the church of St. Apollinare of the late
Roman Empire, in which mother-of-pearl was also employed.