Free Chromatography Catalog
Figure 7. Microphotograph of synthetic Egyptian blue crystals (160 X)
Table I. Results of the Analysis of the Pigments
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Color
Bust location
Red Green
Necklace Headband
Yellow Black Blue
Headband Eyelash Crown
Binding medium for carbon: beeswax
weighing t h e r e q u i r e d portions of t h e r a w m a t e r i a l s a n d of m a i n t a i n i n g rela tively good control of t e m p e r a t u r e a n d furnace a t m o s p h e r e . T h e y also k n e w a b o u t t h e impor t a n c e of a d d i n g fluxes d u r i n g t h e syn thesis. W i t h o u t t h e s e alkali additives, t h e blue p i g m e n t s o b t a i n e d a r e r a t h e r pale because of t h e very small crystals o b t a i n e d . Ideally, for brilliant blue p i g m e n t s , t h e crystals should b e in t h e order of a b o u t 5 - 5 0 μπι in size. T h i s coarser crystallinity is achieved only by a d d i t i o n of fluxes. B e c a u s e its in t e n s i t y d e p e n d s strongly on t h e size of t h e crystals, E g y p t i a n blue is r e g a r d e d t o d a y as a r a t h e r poor p i g m e n t com p a r e d t o cobalt a l u m i n a t e blue or zir c o n - v a n a d i u m blue. While cognizant of t h e technological a c h i e v e m e n t s of our t i m e , we m u s t certainly a d m i r e t h e skills a n d knowhow of t h e a n c i e n t E g y p t i a n s , w h o were able t o p r o d u c e excellent-quality E g y p t i a n blue, a very complex pig m e n t , for over 2000 years a n d use it t o a d o r n t h e b u s t of their q u e e n , Nefertiti. Acknowledgment
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Composition
Iron oxide (Red ochre) Possibly the green basic acetate of Cu (verdigris) Orpiment (As2S3) Carbon CaCu[Si4O10] (Egyptian blue)
W e t h a n k J . S e t t g a s t , director of t h e E g y p t i a n M u s e u m , W e s t Berlin, a n d J . S. Karig, m a n a g i n g director of t h e m u s e u m , for allowing u s t o s a m p l e t h e b u s t of N e f e r t i t i . H.-R. Schulten, Physkialisch-Chemisches Institut
628 A · ANALYTICAL CHEMISTRY, VOL. 54, NO. 4, APRIL 1982
der U n i v e r s i t a e t B o n n , carried o u t t h e m a s s s p e c t r o m e t r i c investigations. W e also t h a n k D . Mueller, F i n n i g a n M A T AG, Basel, for supplying G C / M S spec tra, a n d R. Giovanoli, L a b o r a t o r i u m fuer E l e k t r o n e n m i k r o s k o p i e , Univ ersitaet B e r n , for r u n n i n g t h e E D spectra. T h e t i t r i m e t r i c analyses were carried o u t by K. Mooibroek, and the thermoanalytical measure m e n t s were d o n e by D . Woodtli, b o t h of M e t t l e r I n s t r u m e n t e AG, Greifensee/Zurich. References (1) A. Lucas, and J. R. Harris, "Ancient Materials and Industries," 4th éd., Edward Arnold Ltd., London, 1962. (2) W. T. Chase, "Egyptian Blue as a Pigment and Ceramic Material," by R. H. Brill, MIT Press, Cambridge, Mass., 1971, pp 80-90. (3) W. Noll, "Anorganische Pigmente in Vorgeschichte und Antike," Fortschritte der Minéralogie, 57, 203-63 (1971). (4) L. Borchardt, "Ausgrabungen der Deutschen Orient-Gesellschaft in TellEl-Amarna, III. Portraets der Koenigin Nofret-ete," J. C. Hinrichs'sche Buchhandlung, Leipzig, 1923. (5) R. Giovanoli, and J. Riederer, "Egyptian Blue," Studies in Conservation, in preparation. (6) J. Riederer, "Kunstwerke Chemisch Betrachtet," Springer Verlag, BerlinHeidelberg-New York, 1981. (7) G. Bayer, and H. G. Wiedemann, "Aegyptisch Blau, ein Synthetisches FarbPigment des Altertums, Wissenschaftlich Betrachtet," Sandoz Bull., if», 19-40 (1976).
