Clay is the basic material of pottery and has distinctive
characteristics. It can be moulded and will retain its shape and
it hardens on firing to form a brittle but otherwise virtually
indestructible material that is not harmed by any corrosive agents
that attack metals or organic materials.
is a refractory substance and will vitrify only at temperatures
of about 2,900F (1,600C). It can be mixed with a substance that
will vitrify at a lower temperature when the clay will hold the
object in shape while the other substance vitrifies. This forms
a nonporous, opaque body known as stoneware.
feldspar or soapstone is added to the clay the vitrified product
is translucent and is known as porcelain. Pottery that
is not vitrified is referred to as earthenware and is slightly
porous and coarser than vitrified materials.
clay naturally contains kaolin which provides the whiteness, hence
its use in bone china. Perfectly pure kaolin is necessary
for the manufacture of porcelain and other fine china,
whilst less pure varieties are used in making pottery,
Pottery is made of clay that is permanently hardened
by firing in a kiln. The nature and type of pottery is determined
by the composition of the clay, the way it is prepared, the temperature
at which it is fired and the glazes used. Depending on the clay
used earthenware, when fired, can be buff, red, brown,
or black. Earthenware is the oldest and simplest form of
is a pottery compound that is fired at a sufficiently high temperature
to cause it to vitrify and become extremely hard whilst porcelain,
finer than stoneware and generally translucent, is made
by adding feldspar to kaolin and then firing at a very high temperature.
history pottery objects have been produced by different cultures
using local materials and traditional techniques. Undoubtedly
the most sophisticated pottery culture was in China, where it
has been made since the Neolithic Period. Porcelain was
made in China as early as the 9th century, but its secret was
not discovered by Europeans until the 18th century. Chinese porcelain,
or "china" as it is commonly called, was widely
exported to Europe where it had a influence on European manufacture
wares made before the 19th century fall into six main categories:
lead-glazed earthenware, tin-glazed earthenware,
stoneware, soft porcelain, hard porcelain,
and bone china.
other types of ware, less common than those already discussed,
are slipware and lusterware.
Earthenware was the first kind of pottery made, dating
back about 9,000 years and in the 20th century, it is still widely
is usually glazed to overcome its porosity, which makes it impracticable
for storing liquids in its unglazed state. The fired object is
covered with finely ground glass powder suspended in water and
is then fired a second time. During the firing, the fine particles
covering the surface fuse into a glasslike layer, sealing the
pores of the clay body.
are two main types of glazed earthenware. When the earthenware
body to which this glaze is applied has a cream colour it is covered
with a transparent lead glaze, the product being called creamware.
The second type, covered with an opaque white tin glaze, is called
tin-enameled, or tin-glazed earthenware.
earthenware was made from medieval times onward but fell out
of favour when tin glaze became widely used towards the end of
the 15th century. It returned to popularity with the advent of
Wedgwood's creamware around the middle of the 18th century.
first important tin-glazed wares came from Italy during
the Renaissance, and manufacture spread rapidly, through Europe
to England. Under the name of majolica, faience or delft it enjoyed
immense popularity until the advent of Wedgwood's creamware,
after which the fashion for tin-glazed ware declined rapidly.
all ancient, medieval, Middle Eastern, and European painted ceramics
are earthenware, as is a great deal of contemporary household
Also simply called Delft, it is a tin-glazed earthenware
and was first made early in the 17th century at Delft in Holland.
Dutch potters later brought the art of tin glazing to England
along with the name Delft, which now applies to wares manufactured
in The Netherlands and England, as distinguished from faience,
made in France, Germany, Spain, and Scandinavia, and majolica,
made in Italy.
Stoneware is a vitrified pottery and is very hard
and, although sometimes translucent, it is usually opaque. The
colour of the fired material varies considerably from red, brown,
gray, white to black.
white stoneware was made in China as early as 1400 BC,
the first production of stoneware in Europe not being until the
16th century in Germany. By the end of the 17th century English
potters were making a salt-glazed white stoneware that
was regarded by them as a substitute for porcelain. In
the 18th century, the Englishman Josiah Wedgwood made a black
stoneware called basaltes and a white stoneware called
jasper. A fine white stoneware, called Ironstone
china, was first produced in England early in the 19th century.
Porcelain is a vitrified pottery with a white, fine-grained
body that is usually translucent. The word is derived from porcellana,
used by Marco Polo to describe the pottery he saw in China.
distinction between porcelain and stoneware, the
other class of vitrified pottery material, is less clear.
In China, porcelain is defined as pottery that is
resonant when struck, whilst in the West it is a material that
is translucent when held to the light. Neither definition is totally
correct as some heavy porcelains are opaque, while some
thinly potted stonewares are translucent.
three main types of porcelain are hard-paste porcelain,
soft-paste porcelain and bone china. The terms soft
and hard refer to the properties of the two materials; soft porcelain
can be cut with a file, whereas hard porcelain cannot.
was first made in a primitive form in China between AD 600 and
900 whilst the familiar Western porcelain was not manufactured
until after the late 1200's. It was made from kaolin (white china
clay) and petuntse (a feldspathic rock), the latter being ground
to powder and mixed with the clay.
manufacture of soft porcelain started in the 16th century
in Italy but it was not until the late 17th and 18th centuries
that it was produced in quantity. The secret of true porcelain,
similar to that of China, was discovered about 1707 at the Meissen
factory in Saxony. Later, at the end of the 18th century, Josiah
Spode the Second added bone ash to the hard porcelain formula
to make the standard English bone china.
A hybrid hard-paste porcelain containing bone ash.
The initial development of bone china is attributed to
Josiah Spode the Second, who introduced it around 1800. His basic
formula of six parts bone ash, four parts china stone, and three
and a half parts china clay remains the English standard . Hard
porcelain is strong but chips fairly easily and, unless specially
treated, is usually tinged with blue or gray. Somewhat easier
to manufacture, bone china is strong, does not chip easily,
and has an ivory-white appearance. It has since become the standard
English porcelain. Bone china is popularly used
for table services in England and the United States.