Fig. 5

SEM-EDX of an area of the cross section shown in Fig. 2A. a The BSE image: The thin dark blue–black line visible just above the white ground in the section illustrated in Fig. 2A may be an indigo wash used to lay in the shadows in the drapery. It is dark in the BSE image suggesting it is organic or carbon-based. The large particle of azurite (1) is a mid-grey level. Particles located in the center of the section have a hexagonal form and a brighter grey level than azurite. The white box indicates the area mapped. b Maps of the distribution of Cu, Bi, As, and Ca. Bi and As map to the hexagonal particles in the center of the field of view. c Typical EDX spectrum of the hexagonal particles shows they are Cu-As-Bi oxides. Similar spectra were obtained at all sites labeled 2 in Fig. 2