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Pigment analysis of portrait miniatures using Raman microscopy
Author(s) -
Derbyshire Alan,
Withnall Robert
Publication year - 1999
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/(sici)1097-4555(199903)30:3<185::aid-jrs357>3.0.co;2-u
Subject(s) - raman spectroscopy , vermilion , pigment , malachite , crystal (programming language) , amorphous solid , materials science , chemistry , analytical chemistry (journal) , mineralogy , optics , crystallography , physics , copper , organic chemistry , chromatography , computer science , metallurgy , programming language
Raman microscopy was used for the in situ identification ofpigments and covers of a glazed portrait miniature of Elizabeth I,namely the Armada Jewel, otherwise called the Heneage Jewel. It wasconfirmed that the gemstones on the frame are diamonds and rubiesfrom their characteristic Raman and fluorescence spectra,respectively. The domed cover on the front of the locket wasidentified as α‐quartz crystal from its Raman spectrum,whereas the flat cover on the reverse side is an amorphous glass. TheRaman spectra of the pigments were collected in situ byfocusing the incident laser light through the amorphous glass cover.Nine different pigments were unambiguously identified: white lead,vermilion, red lead, azurite, lazurite, orpiment, pararealgar, yellowochre and malachite. The Raman spectrum of a further, unidentifiedgreen pigment exhibits a band of medium intensity at 969 cm −1 and weaker bands at 596, 546, 476 and 388 cm −1 . It was shown that this pigment is notchrysocolla, atacamite or pseudo‐malachite by comparison oftheir Raman spectra. Finally, the brown pigment used as a dark tonecontains amorphous carbon. Copyright © 1999 John Wiley &Sons, Ltd.