The
variety of porphyry most prized for its beauty, its utichangeableness,
the beautiful polish it takes, for hardness and close texture, is that
which was most generally adopted by the ancients, and is called antique porphyry. This variety is inclined to red or purple, whence the generic name of this stone, from the Greek πορφυρά, which signifies purple.
Red
porphyry, originally from Arabia, was subsequently found in Sweden and
Saxony, where it is procured of a dark colour, and sometimes blackish,
mixed with grains of white. Black porphyry is that stone which the
ancients called ophite, which is the same as serpentine.
The
figured porphyry of Egypt, which must not be confounded with the
figured marble, is most valued when it has numerous yellow marks on a
white ground. That kind with a dark red ground is more common.
The
green porphyry of Siberia, also found in Alvernia, shows spots or
whitish grains on a greenish ground. The green porphyry of antiquity is
now very rare : it is known by its long white square marks, which are
in the form of St. Andrew's cross.
Italy,
France, and some other countries in Europe now yield us porphyry, some
of which rivals the ancient stones in hardness and beauty, but the
greater part are very inferior to them. Italian porphyry, especially,
is almost all very hard and scaly; the variety of a light green, on a
very dark green ground, is so common that it is used in Turin to pave
the streets.
The Romans and Greeks prized highly and used
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