Non‐destructive Chemical Analysis of Old South Arabian Coins, Fourth Century Bce to Third Century Ce

Abstract

Studies on Old South Arabian (OSA) coinage are rare and state‐of‐the‐art materials analysis for them lags far behind that of ancient Greece and Rome. Understandably, numismatists responsible for preserving their collections discourage destructive analyses. We have selected coins of the aesthetically and technically developed Himyarite Royal Raydan series (early first to late second century ce), so‐called Old and New Style Athenian Imitations, among others to provide a wide spectrum of information on OSA coinage. We used non‐destructive neutron diffraction to ascertain the metal compositions and corrosion products. Density determinations using gas‐pycnometry support these experiments. The results provide detailed information with regard to a small, apparently homogeneous, selection of 10 Himyarite period specimens and first insights into the actual and the original metal compositions of about 90 coins of the three main OSA numismatic groups. The analytical results make clear which OSA coins originally were struck and which ones were cast. The analyses provide not only detailed information concerning the manufacture of the selected representative coins, but also suffice to cast a shadow on the reliability of commonplace macro‐optical classification, which proves often to be inaccurate.

The Evolution of Pre‐Islamic South Arabian Coinage: A Metallurgical Analysis of Coins Excavated In Sumhuram (Khor‐Rori, Sultanate of Oman)

“…However, Kirfel et al . () calculated that about a 2.5% phase fraction of their coins were made of metallic lead, corresponding to about 7.7 wt% Pb bulk contents, in agreement with values found in some of our samples.…”

“…In fact, this non-destructive technique does not allow us to detect the presence (if any) of tin in the investigated samples-and this is not a minor drawback, given the relevance of this element in copper alloys! However, Kirfel et al (2011) calculated that about a 2.5% phase fraction of their coins were made of metallic lead, corresponding to about 7.7 wt% Pb bulk contents, in agreement with values found in some of our samples.…”

“…It is not easy to compare our data with Kirfel et al . 's () neutron diffraction analyses of two coins belonging to Hadramawt type 4.0. In fact, this non‐destructive technique does not allow us to detect the presence (if any) of tin in the investigated samples—and this is not a minor drawback, given the relevance of this element in copper alloys!…”

“…It should be noted that the bulk composition of our ‘bucranium type’ coins is different from that reported by Kirfel et al . (). According to the latter authors, in fact, coins from this numismatic series are made of an alloy that is extremely rich in silver (from 35 to 91 wt%).…”

“…Relatively few metallurgical studies have been specifically devoted to ancient (pre-Islamic) South Arabian coinage. Among them, we can mention Grave et al's (1996) PIXE/PIGME study of pre-Islamic silver and billon coins, and two papers dedicated to the analysis of the numismatic collection of the Staatliches Museum für Völkerkunde, Munich (Germany)-one by Munro-Hay (2003), who catalogued coins of 'Arabia Felix', mostly on a stylistic basis; and the other by Kirfel et al (2011), who carried out non-destructive, neutron diffraction analyses of about 100 old South Arabian coins.…”