(Coins)(Byzant) Padfield-Analysis Of Byzantine Cooper Coins By X-Ray Methods 1972.pdf

Analysis of Byzantine copper coins by X-ray methods

Tim Padeld

Abstract

Two methods of analysis are described in this article: X-ray uorescence analysis of the uncleaned

surfaces of copper coins and electron microprobe analysis of small fragments obtained by drilling into

the edges of the coins.

These two X-ray analytical methods are inaccurate when used in this way because the surface of

a coin is chemically altered by corrosion and the interior is generally not chemically homogeneous.

On the other hand, they damage the coin very little. X-rays discolour some minerals, though this

phenomenon is rarely, if ever, observed on coins. The damage done by drilling depends entirely on

the skill of the analyst, because the electron microprobe can analyse a fragment one hundredth of a

millimetre across.

These advantages of minimal damage are useful in exploratory work where the expected return in

information would not justify the destruction or multilation of large numbers of coins for the sake of a

more accurage analysis. In this report 83 coins were analysed for tin, zinc, iron, cobalt, nickel, silver,

lead, antimony, arsenic and cobalt.

A numismatic analysis of the results by Philip Grierson failed to show systematic chemical dier-

ences attributable to the source of the metal but produced one interesting monetary insight: the four

pentanummia of Constantinople and Nicomedia are bronze, in contrast to the higher denominations

from the same mints which are copper.

This is a digital version of the article rst published as: Tim Padeld, 'Analysis of Byzantine

copper coins by X-ray methods' in 'Methods of chemical and metallurgical investigations of ancient

coinage' Edited by E.T.Hall and D.M.Metcalf, Royal Numismatic Society, special publication no 8,

1972

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