X-RAY FLUORESCENT ANALYSIS OF ANGLO SAXON JEWELLERY

X-ray fluorescence analysis of 30 pieces of Anglo Saxon jewellery, from the Ashmolean Museum, Oxford, is followed by a comparison with similar results obtained from contemporary coinage. The standards of fineness for the coinage are applied to the jewellery and used to date its manufacture. An appendix describes repeatanalyses of some coins which, at first, had widely differing results from XRF and specific gravity methods.     

NON-DESTRUCTIVE RADIOISOTOPE X-RAY FLUORESCENCE ANALYSIS OF OLD SILVER COINS

The paper presents the results of a feasibility study of the application of X-ray fluorescence analysis to nondestructive analysis of coins. Radioisotope sources ⁵⁵Fe, ²⁴¹Am, ¹⁰⁹Cd and ²³⁸Pu were used for excitation and a Si/Li detector with a multichannel analyser for the measurement of characteristic X-ray lines. Silver and copper in Polish renaissance coins have been analysed. Analysis using Ag K and Ag L lines allows one to distinguish between blanched and unblanched coins. The accuracy of the silver determination using Ag K X-rays is claimed to be ± 0.5% Ag for homogenous coins and ± 1.0% Ag for blanched but well-preserved uncorroded coins.     

QUANTITATIVE RESULTS OF XRF ANALYSIS OF ANCIENT COINS BY MONOCHROMATIC X-RAY EXCITATION

The analysis by XRF applied to old coins is improved by use of monochromatic X-ray excitation of variable energy. In addition the effects of relief and irregular shape are eliminated. A method of absolute quantitative analysis without any reference standard has been set up. Results of the analysis of 52 early Greek and 4 late Roman empire gold coins are reported.     

AN ANALYSIS OF SOME THIRD-CENTURY ROMAN COINS FOR SURFACE SILVERING AND SILVER PERCENTAGE OF THEIR ALLOY CONTENT

The silver content within the body and at the surface of 22 Roman ‘bronze’coins dating to a.d. 274–305 was determined by X-ray fluorescence to discover whether these coins were silver dipped and/or issued with a deliberately added amount of silver in their alloy. Results of this analysis indicate that antoniniani and fractional coins of the period 274–294 were probably both silver dipped and minted in an argentiferous alloy. Radiate and laureate fractions issued after 295 do not seem to have had an argentiferous alloy, nor does this analysis provide any evidence that they were silverdipped.     

ION BEAM ANALYSIS OF COPPER AND COPPER ALLOY COINS

In recent years ion beam techniques have become more and more important since in most cases the analysis of copper and copper alloy coins has to be non-destructive. It is therefore of interest to study the relative advantages of several nuclear methods for a certain type of metal. The results are presented here of a comparison between three non-destructive ion beam techniques: particle induced X-ray emission, proton activation analysis and fast neutron activation analysis.     

DETECTION OF NEAR-SURFACE SILVER ENRICHMENT ON ROMAN IMPERIAL SILVER COINS BY X-RAY SPECTRAL ANALYSIS*

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.     

COMPARISON OF METHODS OF ANALYSIS OF SILVER AND GOLD IN SILVER COINS

A series of silver coins was analysed for silver and gold contents by three methods—chemical wet analysis, activation analysis and X-ray fluorescence using a point source linear spectrometer (milliprobe). The results indicate that while the X-ray fluorescence technique gives better agreement with chemical analysis for major components the use of activation analysis with automated equipment results in a considerable saving of time and has a high sensitivity for some minor components.     

记新见数枚削刀和原始刀币

近年来,在山西、山东和河北一带陆续见到一些实用削刀和原始刀币。这些刀对于探讨实用刀削和原始刀币之间的关系以及货币的起源问题具有参考价值。现选择数枚简要介绍如下,以飨读者。一、削刀下面介绍的6枚削刀,根据其形状特点,我们暂且将其分为背直首翘式、背弧首翘式、背弧式三种。背直首翘式此式的主要特点就是背部相对较直,刀首上翘(后仰)。山东德州发现一件(图一:1)。背直,首翘。色黑,绿锈。体大,重110克。柄部厚实。刀脊背下部与柄交接处宽厚,往刀首方向逐渐变窄。柄部正背中间各有一条线。柄与刀身衔接处呈一直线形。环厚,环孔小。通…     

X-RAY FLUORESCENCE AND DENSITY MEASUREMENTS ON SURFACE-TREATED ROMAN SILVER COINS*

Some 630 Roman silver coins excavated at Augusta Raurica (Switzerland) have been analysed by non-destructive X-ray fluorescence and X-ray diffraction. Furthermore, the density and the weight have been determined. The measured average density of plated and massive depletion-silvered coins is lower than the density calculated from the chemical composition, whereas massive coins display equal values for both of the densities. Based on experimental X-ray investigations of modern silver (tempering, acid treatment, production of corrosion layers), the nature of corrosion products on silver, their impact on surface analysis, and aspects of wearing-off by circulation are briefly discussed.     

DARK AND SHINY: THE DISCOVERY OF CHROMITE IN BRONZE AGE FAIENCE*

The Late Bronze Age (1550–1200 bc ) in the Near East was a period of cultural development, international trade and technological innovation, notably in metallurgy and silicate technology. As a spin‐off of the new glass technology, new colorants were also applied to faience glazes presumably to increase their aesthetic value. Here, we report on the presence of chromite minerals in the glaze of a faience vessel from Deir ‘Alla, Jordan, 1200 years earlier than reported so far. Importantly, chromite was not only used as a greyish pigment, but also as a nucleating agent for spherulitic crystallization of augite in the amorphous glaze. These synthetic augite formations give a unique, sparkly appearance to the faience vessel, apparently imitating a metallic look. The making of such an intricate glaze and its contemporary significance reflect not only the high level but also the appreciation of innovation in that region at that time.     

RIETVELD X-RAY DIFFRACTION AND X-RAY FLUORESCENCE ANALYSIS OF AUSTRALIAN ABORIGINAL OCHRES*

Rietveld phase analysis of X-ray powder diffraction patterns and chemical analysis by X-ray fluorescence spectroscopy have been used to characterize a series of red and yellow ochre samples from Aboriginal ochre deposits in South and Western Australia. The ochres were found to have diverse mineralogy, being mixtures of up to seven minerals, and also to have complex trace element signatures. The mineralogical characteristics and geochemistry of the ochres can be used to identify the source quarries. Using this combination of analytieal techniques it may be possible to trace the source of ochres in burial sites and on objects back to the original quarries.     

X-RAY FLUORESCENCE ANALYSIS OF MODERN AND RECENT CHINESE PORCELAINS

X-ray fluorescence analysis of modern and recent Chinese porcelains shows that the Mn/Co ratio is about 2.5 and above for those made before World War II and less than 0.7 for those made after the war.