Characterization of azurite and lazurite based pigments by laser induced breakdown spectroscopy and micro-Raman spectroscopy

The most commonly used blue pigments in medieval manuscripts are azurite an d lapis-lazuli. The first one is a copper-based pigment; the coloring compo und of the latter is lazurite, a sodium silico-aluminate in a sulfur matrix . Knowledge of the chemical composition of the materials is essential for t he study of illuminated manuscripts. In this paper, micro-Raman and LIBS ha ve been used for the study of azurite and lapis-lazuli, as well as differen t mixtures of these pigments applied to parchment to simulate an illuminate d manuscript. The results of our work show the importance of using more tha n one technique for a good comprehension of a manuscript. In particular, th e opportunity of combining elemental information (obtained from laser induc ed breakdown spectroscopy) and vibrational spectroscopy information (obtain ed from Raman) will be fully exploited. (C) 2001 Elsevier Science B.V. All rights reserved.