RES and PIXE microbeam analysis is used to investigate the trace element co
ncentrations as well as the surface corrosion of counterfeited copper halfp
ennies from the mid 18th century. PIXE elemental mapping was used to identi
fy regions with a minimum of light element contamination which could be use
d for accurate trace element determinations. RES analysis of selected point
s on the map could be used to confirm the absence of corrosion or contamina
tion, and in addition yielded valuable information on the composition and s
tructure of the corrosion layers. (C) 1999 Elsevier Science B.V. All rights
reserved.