355 
Alabasters and Granites, t^c. at Rome. 
Egyptian Granite. — The columns of the portico of the Pan- 
theon, the Ionic columns of the Temple of Concord in the Fo- 
rum Romanum, and some others at Rome, are of large-grained 
red Egyptian granite, as are the obelisks, the largest wrought 
stones that exist in Europe. This red Egyptian granite, was call- 
ed by the ancients Pyrrhopoikilon, on account of its variegated 
and red colour, and Syenite, because it was got in the quarries of 
Syena, in Upper Egypt. Pococke describes the quarries of gra- 
nite which he visited at Syene. Some other kinds of granite 
from the east occur amongst the remains of ancient art at Rome, 
but not so frequently as the red Egyptian granite. The Ro- 
man marble-cutters saw blocks of antique granite by means of 
an iron blade and emery, as calcareous marble is sawed by an 
iron blade and siliceous sand. The hardness of granite renders 
the operation of sawing it very tedious. 
Elba Granite. — There are some columns of JEthalian, or 
Elba granite, at Rome and Pisa. It is small-grained, and call- 
ed, at Rome, Granitello. 
Syenite of Mineralogists. — The syenite of the two lions, at 
the ascent to the Capitol, differs from the granite of the obe- 
lisks, and is like the stone of which the Egyptian colossal head, 
now (1818) in the British Museum is formed. 
Basalt. — There are several ancient Egyptian sphinxes, and 
other figures, and labra balnearia, or bathing troughs, of a dull 
greenish basalt. Basalt is characterized by Pliny as resembling 
iron in hardness and colour ; it more especially resembles cast 
iron. Strabo mentions a quarry of millstones which v/ere, per- 
haps, of basalt, at the Black Promontory in Ionia. 
Touchstone. — Pietra di Paragone, black touchstone, occurs 
in slabs and figures. 
Porphyry. — The columns of porphyry at Rome are not 
nearly of so large a size as the large columns of granite. The 
urn of Constanza and the urn of Helena is each composed of a 
very large block of porphyry ; and the great tazza or saucer- 
shaped reservoir in the rotonda of the Museo Pio-Clementino is 
of one great piece of porphyry. Pliny says that sculptors began 
to work in porphyry only in the reign of Claudius. Vopiscus 
mentions porphyry. The room in which the princes of the 
Greek empire were born was incrusted with porphyry, and the 
princes born in this rponi were called Porphyrogeneti. The 
