Interesting how brass rears its ugly head from time to time - just when you think it's terribly passe and we should all go study lipids or something.
With reference to Robert Maddins comments, I also analysed some of the Masada brass armour scales as part of a project looking at the Roman military copper-alloy metalwork from Masada (data and brief discussion as research note in Archaeometry 1998, 1). The analyses were by ICP-AES and gave zinc contents of between 17.9% and 22.6% (17 scales). This is entirely consistent with Roman type cementation brasses of course, and, indeed, fits well with much of the other material analysed. More interestingly, the scales do form an interesting sub-group quite distinct from the rest of the Roman brasses on the basis of their iron and manganese contents. As you all know, fe and mn have been identified as indicators of calamine cementation (Carradice and Cowell 1987 etc.) - however, the level of mn, in particular, is significantly higher in the scales than in the rest of the Roman cementation brasses (which are comparable to European Roman brasses). The mn in the scales is present in microscopic (1-2 micron) inclusions of what is predominantly copper sulphide. I've found similar inclusions in contemporary Roman brass coins - but without the mn (mn seemingly in the bulk - or in even smaller inclusions?). This is slowly ongoing research of mine - but I thought I'd throw it out to see what others think?
Dr. Matthew Ponting
Department of Archaeology
University of Nottingham
University Park
NOTTINGHAM NG7 2RD
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Fax: (0115) 951 4812
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