Natural Science in Archaeology

1.3 The Ancient Authors 11
sources. It covers common and less common stones, marbles, gems, glass, and metals.
Amber is included under metals. Stones were generally classified by color.
Isidore echoes Pliny’s skepticism about “magical” properties of stones and adds
the “current” Christian position that reflected an uneasiness about transmitting what
they believed were pagan superstitions. He contributed nothing about earth materials
not already given by Pliny, six centuries earlier. However, scientific understanding
had been in decline the whole time between Pliny and Isidore, so he can be credited
with restoring some of the “lost” knowledge.
1.3.2.2 Albertus Magnus (ca. 1206–1280)
Known as Albert the Great, this scientist, philosopher, and theologian studied at
Padua and later taught there and at Bologna and Cologne. After joining the Dominican
Order he was sent to the University of Paris where he read the translations of
the Arabic and Greek texts of Aristotle. While in Paris he began a compilation of
the entire body of information then known about natural science, logic, rhetoric,
mathematics, astronomy, ethics, economics, politics, and metaphysics. He wrote
commentaries on all of Aristotle’s known works, supplementing them with personal
observations and experiments. Among his scientific works is the Mineralium (or
Book of Minerals), modeled on Aristotle, which was the most influential book on
minerals until their systematic study by Agricola. This work is divided into five
books, some of which are subdivided into tractates, and single tractates are subdivided
into chapters.
Tractate 1 of Book 1 considers stones in general and presents the characteristics
of minerals that were considered essential, i.e., inherent in their nature, such as their
composition, greater or lesser transparency, substance, and occurrences. The second
tractate considers their accidental properties, among which are: cause of color,
fissility versus nonfissility, porosity or compactness.
Book 2 is devoted to precious stones. The first tractate examines the cause of
the powers in stones. “The compilers of popular lapidaries transmitted some factual
information; but their chief interest was the curative or magical powers of stones”
(Wyckoff 1967:xxxiv). Albertus was therefore concerned with accounting for these
so-called powers. His primary argument is a denial that these stones had an inherent
soul (anima), but that its form caused each stone to be unique. “In this sense, then,
the forms of stones account for whatever effects they produce. An excellent example
is the “power” of magnetism, essential to an identification or definition of the
mineral magnetite” (Wyckoff 1967, p. xxxiv). The second tractate is an alphabetical
lapidary of precious stones that gives all the information on each gem gleaned from
classical literature and previous Medieval lapidaries to which he added his own
observations. The final tractate of this book treats the images or “signs” in stones,
stone carving, and the meaning of these images.
Book 3 is devoted to metals in general, with the first tractate paralleling Tractate
1 of his book on stones, giving the plan of the book, its essential characteristics, the
classical opinions about the composition of the metal, and the places where metals