Natural Science in Archaeology

7.9 Lead (Pb) Minerals 177
Lead has been detected in bones from Roman archaeological sites (Aufderheide
et al. 1992). For a comprehensive look at lead and lead poisoning in antiquity, see
Nriagu (1983). This book has hundreds of references and a bibliography of ancient
authors.
Lead-tin pewter has been used at least since Roman times. The amount of lead
in good pewter does not exceed 10%. A dark, soft pewter, known as ley, contains up
to 50% lead. If small amounts of copper are added, a hard pewter is formed, while
small amounts of antimony lead to a silvery luster. The amount of lead in pewter
tended to be related to the purpose of the object. The Chinese began making pewter
in the Han Period. As was the case in the Mediterranean region the early Chinese
obtained much of their silver from argentiferous galena.
Pliny notes that lead oxides were used as paints. Nriagu (1983) gives an extensive
treatment of the use of lead oxides in antiquity. Three lead oxides were used in
antiquity: minium (Pb 3 O 4 ) is scarlet red, massicot (PbO) is yellow to reddish-yellow,
and litharge (PbO) is red. Litharge (PbO), called red lead, has been widely used
since ancient times as a red pigment, even though it is quite toxic (see Chap. 9).
Natural litharge forms in the oxidized zone of lead ore deposits. By Roman times
red lead was also being manufactured from other lead minerals such as cerussite
(lead carbonate). As can be seen from many ancient texts, women in ancient Greece
used white lead (lead carbonate) in cosmetics (e.g., in Plato’s Lysis, Xenophon’s
Economics, Aristophanes’ Ecclesiazusae). The mineral cerrusite has been frequently
referred to as white lead (PbCO 3 ) or white lead spar.
Willies (1984, 1989) reports finding evidence of late first millennium BCE mining
for lead and zinc at the Zwar Mines in Rajasthan, India. The weathered zone
included oxidized lead ores, anglesite (PbSO 4 ) and smithsonite (ZnCO 3 ), but the
principal ores appear to have been sphalerite (ZnS) and galena (PbS).
There are numerous lead/zinc deposits in southwest China and lead/silver deposits
in southeast China. Ancient Chinese texts occasionally referred to the mining
of lead and silver. It should be noted that Chinese bronzes, beginning in the Late
Shang and Early Zhou Dynasties, are ternary Cu/Sn/Pb rather than the binary Cu/Sn
bronzes of the eastern Mediterranean and Near East regions. Nriagu (1983) devotes
a chapter to detailing the lead resources in antiquity of more than 20 countries. The
ancient Chinese used lead oxides as pharmaceuticals (Needham 1974) and to dry
oil paints. During Zhou times, lead vessels and vases were cast in the same shapes
as the bronzes.
Galena (PbS). Galena (lead-glance) has a hardness of 2.5 and density of 7.59.
It is a very common metallic sulfide frequently associated with silver minerals. The
Romans gave the name galena to this lead-ore mineral. It is easily recognized by its
perfect cubic cleavage, high density, and silvery metallic color. It is one of the most
widely distributed sulfide ore minerals. Galena was used in antiquity in the Old
World as eye paint and as ornaments. In Pharaonic Egypt, galena was mined at Gebel
Zeit from approximately 1000–1200 BCE. In a study of two of the mining sites, Castel
et al. (1988, 1989) found that at site 1 it was possible to reconstruct the history of
the ancient mining, because the mines have not been worked in modern times. At site
2 about 600 old workings were found. The galena was used to make kohl.