Natural Science in Archaeology

1.3 The Ancient Authors 9
process of smelting. He discusses the various techniques for discovering metals,
from searching on the surface for indications of minerals to various methods of
discovering underground sources.
Pliny discusses no less than 77 minerals used in medicine. Overall he gives the
Latin name of more than 350 minerals. This list includes some rocks as well as natural
products like petroleum. The more than 350 Latin names do not translate into
that number of species in English. For example, there are 10 agates, 6 amethysts, 15
coppers [including bronze], at least 20 different marbles, and so forth.
Pliny attempted to apply scientific observations to his geologic studies. He interjected
his own observations into his research and adopted a method of classifying
gemstones that named them from parts of the body (N.H. 37.186), after animals (N.H.
37.187), and after a resemblance to inanimate objects (N.H. 37.188). He also notes
that there are several tests to determine whether a gemstone is genuine: by weight
(i.e., density), coldness, or by physical characteristics such as color. Pliny was, however,
inconsistent or confused in the naming of some minerals. His “sapphirus” is not
sapphire. He accepted that rock crystal was a hard form of water. Another interesting
belief of his was that marble regenerated itself in certain quarries. Nevertheless he
was suspicious of claims that certain minerals had magical properties.
Pliny used several tests to identify minerals. Among these are the use of luster
(pearly, dull, metallic, greasy), transparency, hardness, streak, crystalline form,
form (granularity, flake, powder), cleavage or fracture, and friability. If the mineral
had special characteristics such as magnetic attraction, these are also noted. He
made a major advance in describing the nature and form of crystals and was puzzled
by the lack of symmetry in the terminations of quartz crystals.
Unfortunately, supposition and fiction are intermingled in his scientific observations.
In general, each mineral name is given, sometimes with its derivation or
foreign appellation, its geologic and geographic sources, properties, medical use
(if any), uses other than medical, and its folklore or alleged magical properties. In
some cases Pliny provided the formula for the preparation of a synthetic pigment.
An example is the formulation of verdigris by exposing copper to an acetic solution
[probably vinegar]. In addition to supposition and fiction mingled with facts
and scientific observations, his mineralogic concepts are sometimes flawed, such as
in instances when he classifies several minerals under one heading (e.g., adamas,
smaragdus). However, some of the physical properties he noted and tests he performed
are still utilized today.
He discusses many rocks in Natural History; not all of his conclusions have
stood the test of time – he considered basalt to be a “black marble”. Pliny died in the
79 CE eruption of Mount Vesuvius. The term “Plinian Eruption” used to describe
violent eruptions is named after him and/or Pliny the Younger.
1.3.1.4 Vitruvius (ca. 70–25 BCE)
Marcus Vitruvius Pollio served as an artillery engineer under Augustus. His De Architectura
Libris Dicem (Ten Books on Architecture) meticulously describes existing