Vitreous Composition.
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Detalle del trono de Tutankhamon
Madera recubierta con hoja de oro, piedras semi preciosas
y pasta de vidrio multicolor
Imperio Nuevo
Museo del El Cairo, Egipto |
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Sarcófago de Tutankhamon |
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Egyptian faience or vitreous composition
was not thoroughly studied until recent times. European archaeologists
gave faience its name because it resembles the European tin-glazed
earthenware ‘majolica’ or European faience. However,
the term is incorrect, because the Egyptian faience is not pottery;
it was made out of glass paste rather than ceramic paste as
used for ‘majolica’.
This technique was developed by the Nagada and Badarian civilizations
from the years 5500 to 3500 BC. The glass paste obtained was
called “tjehenet” by the Egyptians, term that defines
something glossy and dazzling. It was elaborated using ground
quartz mixed with small quantities of lime and natron or incinerated
vegetables. The ashes, from which they obtained soda, came from
Al kali, a plant that grew in Egypt.
To produce a piece of faience, first quartz had to be grounded
until a very fine dust was obtained, then it was mixed with
soda and lime. By adding water to this mixture, a paste that
could be shaped by hand or casted on clay moulds was obtained.
The piece was then covered with a green or blue glaze made of
a similarly produced material, in other words, silica, soda
and lime. These three minerals are today the basic components
of glass. Afterwards, the faience piece was fused in a furnace
reaching a temperature of almost 900º C (1650 º F), a temperature
that was not high enough to totally frit the piece, but that
produced a vitreous effect on the piece surface. The cast glass
technique was used in other cases, and was probably the first
to be used since it is very similar to other techniques already
in use in the fabrication of metals. To elaborate a piece of
cast glass the mix was poured in a crevet to be smelt and then
pressed into moulds to obtain the desired shape. Now a day,
the elaboration processes of these pieces because of its complicated
technique astonish scientific researchers at the Cairo Museum.
Also amazing, is the clearness of the glaze in the finishing
process of the pieces. According to chemical studies, the glaze
shows a 0.5% content of lead oxide, which is a most interesting
fact, since to our days lead is used to dispense clearness to
glass. This fact is of utmost importance as outstanding evidence
that the Egyptians did not fabricate transparent or translucid
glass in large outputs, not because they didn’t master
the technique but because it was more important to use it for
religious purposes.
Faience items produced from quartz dust and those produced with
glass paste from silica were very much related to jewelry. Both
were mainly used for ornaments for the funerary equipment, such
as flasks for perfume, unguent and balsam jars, makeup jars,
amulets, necklaces, rings, masks and even sarcophagus, such
as Tutankhamun’s, which was made out of gold, decorated
with studded semiprecious stones and coloured glass applied
in cavities called ‘grooves’. All these items were
highly valued by the Egyptians because they were considered
as eternity symbols and bestowed protection for the dead during
millions of years, protection against all dangers they could
encounter on their way to eternity.
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