Natural Science in Archaeology

5.5 Oxide Minerals 113
Freshwater pearls were collected by Native Americans. They have been found in
the ancient burial mounds of the Hopewell people in Ohio. Conversely, aboriginal
peoples of Australia regard pearls as a nuisance since they occasionally cracked
their teeth on them while dining on north coast oysters (Ward 1985). Freshwater
pearls have also been found in rivers in the British Isles and continental Europe.
Although the technique for growing cultured pearls was not developed by the
Japanese until the early twentieth century, the Chinese developed a method for making
“pearl” Buddhas as early as the twelfth century. A tiny carving or metal casting
of a Buddha was cemented to the inside of a freshwater mussel until it was coated
with nacre (Ward 1985). These were used as amulets and decorations.
Azurite, Cu 3 (CO 3 ) 2 (OH) 2 , has a hardness from 3.5 to 4 and a density of 3.77. It
is found in shades of light to dark blue. Pliny states that cyanus (azurite crystals)
came from Scythia, Cyprus, and Egypt. Lapis Armenius came from Armenia and
Spain (N.H. 35.47).
Malachite, Cu 2 CO 3 (OH) 2 , has a hardness between 3.5 to 4 and a density of 4.05. It
is bright green to dark or blackish-green in color. Its name is derived from the Greek
mallow (green). In the New World, the deposits exploited between 200–800 CE
near Chalchihuites, Mexico, included malachite (Weigand 1994). Malachite was
used in the Old World at least as early as the fifth millennium BCE. Malachite
occurs in Sinai, Egypt. It was rarely used for jewelry by the Egyptians, although a
few Predynastic beads and several later ornaments are known (Lucas 1989). Pliny
does not list a source for molochitis (N.H. 37.114). He mentions a number of other
materials that could have been malachite. Pliny identifies chrysocolla as coming
from Cyprus, Armenia, Macedonia, and Spain (N.H. 33.4, 86–93, 161; 35.30, 47,
48). He also mentions chalcosmaragdus from Cyprus (37.74). Cosmetics and paint
pigment were made from malachite, and it was carved into beads, gems, and decorative
objects.
Gypsum, CaSO 4 ·2H 2 O, has a hardness of 2 and a density of 2.32. The name
comes from the Greek word for plaster. Alabaster is a compact, fine-grained variety
of gypsum. It is found in white, cream, or variegated colors. Its ancient name
was originally given to several materials from which ointment vases called “alabastra”
were made (from alabastron), but its name may ultimately derive from a
town in Egypt. Alabaster occurs abundantly in the Eastern Desert of Egypt and at
El-Amarna. Jewelry and furniture inlaid with alabaster were found in the tomb of
Tutankhamen. Beads are known from the 18th Dynasty and later (Lucas 1989).
Cylinder seals, carvings, statues, and small decorative objects were carved from
alabaster. It was also used for beads and jewelry inlay.
5.5 Oxide Minerals
Hematite, Fe 2 O 3 , varies in hardness from 5 to 6 and has a density of 5.26. It is
steel gray to iron-black and sometimes appears rusty or iridescent; thin fragments
can appear deep blood red. Massive and earthy material is dull brownish-red to