Natural Science in Archaeology

132 6 Soft Stones and Other Carvable Materials
The floor of the Great Bath, located on the citadel at Mohenjo Daro, is built of
two layers of brick cemented by a mortar of gypsum. During the first century CE,
construction of roads in India also made use of gypsum and other adhesives (Forbes,
in Singer et al. 1954). Gypsum was mixed with glue to make gesso, a fluid, white
material applied to smooth surfaces as a ground for artistic paintings or for gilding.
Carved wooden sculptures of seated Kuanyin from the Song Dynasty in China were
covered with gesso before they were painted or gilded. Tempera painting on a gesso
ground was especially popular in the Middle Ages.
In North America, gypsum crystals were often found on archaeological sites
along the Missouri River near South Dakota. Although their use has not been ascertained,
these crystals were located near house sites, and ethnographic analogy suggests
they may have been ground into a fine powder and used for cleaning and
polishing projectile points, or perhaps to polish quill work (Porter 1962).
6.5 Limestone and Marble
Limestone and marble, made up exclusively or mostly of the mineral calcite [hardness
3], are easy to sculpt if the material has enough cohesiveness. The Venus of
Willendorf statuette (Fig. 6.5) was carved from an oolitic limestone.
The very much larger limestone head (Fig. 6.6) is from first century BCE
Turkey.
Because it takes a high polish, marble was one of the preferred raw materials
for decorative stone, statues, and portrait busts during antiquity. It can be found in
deposits of wide aerial extent that are relatively free of cracks and easy to quarry. The
use of marble in the minor arts was varied. However, it was principally employed
in antiquity to finish temple fronts, and the exterior of civic buildings and for the
production of monuments, columns, and reliefs, interior embellishment, statuary,
busts, stelae, furniture, tabletops, and novelties.
Marble was employed during the Neolithic Period to carve stone vessels and lamps.
The Egyptians and Mesopotamian civilizations used white marble for sculpture and
Fig. 6.5 Three views of the
Venus Willendorf (Austria),
carved from a non-local
oolitic limestone about
22,000–24,000 BP, it was
tinted with ochre