Chemistry Reference
In-Depth Information
fire are usually of a lighter and duller color. There is evidence on the man-
ufacture and use of fired bricks as early as the sixth millennium B.C.E. in
Mesopotamia, the Middle East, and Egypt, and its later spread to Rome,
India, and China.
Earthenware
When the same ceramic paste that is used for making terracotta is fired at
higher temperatures (above 950°C), the material obtained is known as
earth-
enware
(see Fig. 55).
Earthenware
is more vitrified and therefore less porous
and stronger than terracotta, although it is also opaque. Its porosity gener-
ally varies within the range 5-10%. Earthenware is often glazed.
Two particular types of archaeological earthenware, among many
others, are
majolica
and
faience
. During the Middle Ages the terms
majolica
FIGURE 55
Earthenware.
Large earthenware vessels from the sixth-fourth centuries
B
.
C
.
E
., recovered from under the Mediterranean Sea, at Caesarea Maritima, Israel. Earth-
enware one of the simplest types of ceramic material, is highly porous and permeable.
It is made from clay and a variety of additives fired at about 950°C. Iron oxides impu-
rities in the clay usually make earthenware buff, red, or brown. Most earthenware, like
the vessels shown, was not glazed but, if required, sometimes was waterproofed or
decorated with a layer of glaze.
