Processing cathodoluminescence imagery in ancient material analysis

Cathodoluminescence (CL) is quite a well-known phenomenon which can find applications in the study of cultural heritage materials such as ceramic, glass, stone... The classical approach when investigating the nature of these ancient materials is mainly to use petrographic microscopy, X ray diffraction and scanning electron microscopy with energy dispersive X ray spectrometry. To these methods is added the cathodoluminescence imagery which today appears as compulsory, notably for any ceramic study when provenance and making processes are searched for. Applications to ceramic series from Peru (Mochica period) and from Syria (chalcolithic and first millennium BC period) are here shown. Some more exotic materials like marine shells from the antique port of Delos are presented; they will be used to produce radiocarbon dates only if we can demonstrate their structure is homogeneous. Another specific case concerns the chemical nature and the making of glass pearls from Quebec (17th c. AD) which were used as exchange money against furs. This is a methodological aspect which is here enhanced as it is the whole investigation process which is renewed. In each case, the CL imagery proves essential to bring data that the human eye could hardly detect or that would be completely overlooked with the afore-mentioned methods.