Analysis of Ancient Faience

Two analytical techniques were employed to exam ancient faience artifacts from the Petrie Museum:

Optical analysis
Using a magnifying glass and optical microscope proved to be very useful to study the surfaces and the exposed area resulted from chipping or breaks. This examination helped in identifying the materials and the technological features (see What).

SEM analysis
The objects were examined by the scanning electron microscope (SEM) in the Wolfson Archaeological Science Laboratories at the Institute of Archaeology. This examination helps to characterise the different areas in the artefact i.e surface, glaze, interaction zone and core paste. Also the elemental analysis reveals information on the composition and the raw materials.

For this study we used, a Hitachi S-3400N SEM attached with an Oxford instrument of energy dispersive spectroscopy EDS. The samples and objects were examined at working distance of 10mm without a conductive carbon-coating using a low voltage of 3-10kV to minimize charging. We used secondary electron imaging (SE) to distinguish various particles in the core paste, interaction zone or in the glaze layer. Also we used backscattered electron imaging (BSE) to help in identifying differences in particles compositions. Then EDS was used to generate elemental composition of certain areas of the samples to understand the chemical structure of the samples and the distribution of elements across the different zones. However this data is generally qualitative due to the irregular surfaces of the examined samples.
Samples preparation and analysis:

The samples examined for this project included:

• Faience frog amulet UC1176
• Faience frog fragment UC23659
• Terracotta mould UC24141
• Terracotta mould UC47126
• Terracotta mould UC24109
  

Faience frog amulet UC1176
Analysis of surface at three areas to identify the colouring oxides:

Spectrum processing
Processing option: Oxygen by stoichiometry (Normalised)

Discussion
The analysis shows that:

• Copper oxide is the colourant used to obtain the blue glaze on the amulet
• Lead oxide and higher amounts of copper oxide and iron oxide were used for the eyes to give the green-colour glaze

Faience paste in ancient moulds
2mm samples were removed from the moulds and examined in the SEM:

Sample from a mould found at Amarna for ring shank UC24141

Sample from a mould found at Amarna for a flower petal UC24109

Sample from a mould of Bes found at Amarna UC47126

Spectrum processing
Processing option: Oxygen by stoichiometry (Normalised)

This page last modified 6 November, 2009 by Kathryn E. Piquette