IDENTIFICATION OF COBALT-COLOURED EGYPTIAN GLASS OBJECTS BY LA-ICP-MS: A CASE STUDY FROM THE 18TH DYNASTY WORKSHOPS AT AMARNA, EGYPT

Abstract

This paper presents the elemental composition of a representative group of glass-working and -production
samples from Amarna in the collection of the Ägyptisches Museum und Papyrussammlung Berlin, obtained
by quantitative laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). These analyses
were carried out to verify the results from a set of on site analyses of glass objects at Amarna, carried out by
pXRF. The main research question of this study was whether the various sources of Co-ore can be identified
using transition metal data from pXRF analysis only. The 40 samples from the Berlin collection were
confirmed as belonging to the group of Type A, Co- and Co-Cu coloured glass objects, produced in the
Egyptian 18th dynasty, coloured with cobalt-containing ores originating from the western desert in Egypt
(close to the Dakhla and Kharga Oases). The element composition revealed correlations between Co and Al,
Mn, Fe, Ni and the REEs. However, the major, minor and trace element composition revealed no further
distinction between the various workshops in the collection, indicating that similar recipes and raw
materials were used in the workshops at Amarna. Thus, quantitative pXRF using Co, Ni, Mn and Zn
concentrations alone, such as by pXRF, can be used as an indicative instrument for provenancing cobalt in
glass objects, directly on site of objects that cannot be removed from a site or a museum collection.