Premium
DETECTION OF NEAR‐SURFACE SILVER ENRICHMENT ON ROMAN IMPERIAL SILVER COINS BY X‐RAY SPECTRAL ANALYSIS *
Author(s) -
KLOCKENKÄMPER R.,
BUBERT H.,
HASLER K.
Publication year - 1999
Publication title -
archaeometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.716
H-Index - 67
eISSN - 1475-4754
pISSN - 0003-813X
DOI - 10.1111/j.1475-4754.1999.tb00985.x
Subject(s) - analytical chemistry (journal) , silver oxide , materials science , wavelength , mineralogy , x ray , numismatics , chemistry , optics , art , physics , optoelectronics , organic chemistry , chromatography , classics
A collection of 218 Roman imperial silver coins, covering three centuries, was analysed non‐destructively by two variants of X‐ray spectral analysis. Electron beam excitation and energy‐dispersive spectrometry was used for the analysis of the uppermost thin layer (3 μm) of each coin, while X‐ray tube excitation and wavelength‐dispersive spectrometry was applied for the analysis of thicker layers (30 μm), Ag and Cu as major constituents and 18 minor elements were determined quantitatively. Comparing the silver content of the obverse and the reverse of a coin, inhomogeneities could be identified. By comparison of the silver content of the upper thin and the thick surface layers, near‐surface silver enrichment could be detected. Inhomogeneities and enrichments increase in the second and more so in the third century. A large scatter of the silver content and silver enrichment for coins of the same emperor was attributed to varying abrasion of Ag‐enriched layers of the individual coins during decades of circulation.