As part of the visiting Pharaoh exhibition from the British Museum, our local museum hosted a faience workshop this weekend, run by a local ceramicist with an experimental archeologist and an art tutor. Faience is a type of ceramic that was made by the Ancient Egyptians, and is halfway between silica sand and glass. A mixture of silica, metal oxide for colour, potash to lower the flux temperature, and stabilising agents are mixed with water to a fairly dry clay and fired to 1000 degrees celsius after moulding. The silica partially melts to create an opaque, self glazing material. The metal oxides form salt crystals on the surface of the clay as it dries, and creates the colour when fired. Here we have mainly used copper oxide to make turquoise and cobalt oxide to make a deeper blue. Magnesium oxide paint was applied prior to firing to create dark grey marks. During the firing, shell is used as the beads do not stick to it.
The clay is incredibly temperamental, and having used it I have a new respect for the Egyptians who created such ornate designs. If the clay is worked at all heavily, it crumbles and cracks, but can be restored to a malleable smooth clay by gentle patting. It is so soft, that if the reed I used to mould my beads around was lifted, you could see the bead start to sag. It was difficult to make impressions in the clay as too much pressure caused cracking, and too little meant the marks were undefined. The clay would then stick to the mould, making it hard to release.
Despite these problems, I managed to finish the day with seven reasonable beads. The leaf bead had partially exploded in the kiln, which happens if the clay has not quite dried out enough before firing, but it was salvagable. I superglued seed beads in complementary colours to the broken surface, and I think the finished piece is much more interesting as a result.