Since the early Stone Age, approximately 100 000 BC, and within nearly every age and culture, beads have existed. They are the earliest objects of adornment, and as human-made artefacts, are even older than actual pottery. Thus, it stands to reason that one of the first ever man-made materials, Egyptian Faience, was used in the manufacture of beads.
Egyptian Faience was a development of the Mesopotamian technique, and is not to be confused with the Faience ware being produced at Faenza in Northern Italy during the renaissance period, which was a majolica and tin-enamel type of earthenware vessel. The first Egyptian Faience beads came from Badari, in Upper Egypt during the Old Kingdom.
Self-Glazing Clay
True Egyptian Faience is composed of a siliceous body of quartz in powder form, which is self-glazing. The body fuses and vitrifies during firing, creating a bright turquoise blue colour which is the result of copper carbonate infusing the body. There are variants of this blue-green artwork, for example, Faience was followed – and to a large extent, replaced – by a deep blue-green glaze which, unlike the original Faience, was separate from the actual clay body.
Characteristics of Egyptian Paste
The main components of Faience were soda ash, sand and clay, and were easily accessible in ancient Egypt. Because of the large quantities of potash and soda in the glaze, it had a low melting temperature and very distinctive qualities, for example a characteristic glassy appearance, very fluid melting tendency, softness within the glaze and an inclination towards crazing. The advantage was the deep, brilliant colour given off by the addition of colouring oxides.
Crushed Quartz
Glazes such as the aforementioned depend on an alkali as a flux, such as sodium, as opposed to lead. The raw materials used to create the Egyptian Faience body included pure crushed quartz in a virtually pure state, with a small percentage of lime and soda added. This is known as natron, a saline incrustation comprising both sodium carbonate and sodium bicarbonate.
Sodium chloride (household salt), sodium sulphate and silica are all common to natron, which, as an alkali, was added to act as a binder which would cause the quartz to be more plastic as clay was not present in a significant quantity. Salt is also used as a binder, and is in fact still utilised by the modern day Egyptian Faience forgers at Qurna. Natron works on the principle that the soluble sodium salts will have a chemical reaction with the quartz when heated, the result of which is sodium silicate, or glaze.
The Addition of Colour
The colouring oxides are added to the body containing the natron, resulting in a body which is homogeneously coloured when fired. The soluble fluxes, in the form of the salts, along with the copper compound, will travel to the surface as the body dries, creating a white, powdery residue which must not be handled. This is what forms the glaze, and when completely dry is fired in an oxidising atmosphere between 880° and 950°C.
The salts present on the surface layer act as a flux, causing the surface to fuse forming a glassy layer which has been coloured a deep blue by the addition of small amounts of oxides, such as copper for turquoise, or manganese for purple.
The self-glazing quality of Faience is what prevents the gummy, gelatinous quality which sometimes occurs when a glaze is applied too densely, or unevenly, and leaves even the finest incised design in sharp, precise detail, a quality which is often lost during the glazing process.
Egyptian Faience Recipe
- Fire to Cone 08 (950°)
- Potash Feldspar 35gm
- Silica 35gm
- China Clay 10gm
- Ball Clay 5gm
- Sodium Bicarbonate 6gm
- Sodium Carbonate 6gm
- 6% Copper Carbonate added for the traditional deep turquoise colour. Alternatively, for royal blue add 1% cobalt carbonate, or 3% chrome oxide for emerald green.
Resources:
- Cooper, Emanuel A History of World Pottery Batsford (1988)
- Clark, Kenneth A Potters Manual Little Brown (1983)
Mellissa Bushby - Mellissa Bushby is an author, illustrator and ceramicist. She studied Fine Art for four years, and her newest book release is January ...
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