On Food and Cooking

compounds, notably the oxides of silicon,
aluminum, and magnesium. Glass is a
particular variety of ceramic whose
composition is more regular, and usually
includes a preponderance of silica (silicon
dioxide). Until fairly recently, these materials
were made from naturally occurring mineral
aggregates: the word ceramic comes from the
Greek for “potter’s clay.” The molding and
drying of simple clay pottery, or earthenware,
dates from about 9,000 years ago, or about the
time that plants and animals were first
domesticated. Less porous and coarse than
earthenware, and much stronger, is stoneware,
which contains enough silica and is fired at a
high enough temperature that it vitrifies, or
becomes partly glass. The Chinese invented
this refinement sometime before 1500 BCE.
Porcelain is a white but translucent stoneware
made by mixing kaolin, a very light clay, with
a silicate mineral, and firing at high kiln
temperatures; it dates from the T’ang Dynasty