Chemistry Reference
In-Depth Information
The actual process of making coins, known as
coining
, may be carried in
two different ways: either casting the molten metal, or working the solid
metal by compression, that is, in antiquity, by hammering by hammering
(see Textbox 38) (Cooper 1988; Oddy 1980). Although much numismatic
research was conducted in the last few centuries, the main concern in numis-
matic studies involved the examination of inscriptions, denominations, and
types (Cassey and Reece 1988). The composition of the coining metals and
alloys is, however, of not less importance than their design. Studying the
chemical composition of ancient coins can provide useful information on a
variety of ancient technological aspects:
1.
Composition usually reflects the level of development of the metal-
lurgical technology and the economic trends at the time when, and at
the place where the coins were struck.
2.
Compositional variations in sequential coin issues, say, from year to
year, may reflect differences in the source of the ores from which the
coinage metals or alloys were extracted.
3.
Compositional variations within a single coin issue point to variations
in the quality control of the metallurgical processes.
4.
Compositional differences of particular coins make it possible to rec-
ognize imitations and fakes.
The reluctance of museum curators and collectors to allow permanent
damage to antiquities was, until not long ago, the main reason for the small
amount of analytical work done on ancient coins. This was understandable
since performing chemical analysis required removing a sample from the
coin or damaging its surface, which meant either the destruction or deface-
ment of, at least, a portion of a coin. More recently, however, a number of
nondestructive methods of analysis such as neutron activation, X-ray fluo-
rescence, and some techniques of surface analysis have been successfully
applied to obtain information about ancient coins and the people and soci-
eties involved in their production (Carter 1993; Barrandon et al. 1977).
