is unaccountable why the Romans should have considered the Basalt as an
exclusively Ethiopian production, when precisely the same rock was
being quarried a few miles off in the Campagna (near Baccano), in vast
quantities, to pave their roads, the " silex " of the Via Appia being a
true Basalt. Perhaps, however, these suburban quarries did not supply
masses of sufficient dimensions to be worked into statues ; and it is
still more likely that all the sculptures in Basalt known to the Romans
had been executed in Egypt, which would to a certain extent have
prevented their discovering what really was the material.
Basalt more probably took its name from its resemblance in colour to the black pebble
used by the Greeks for testing coin upon, which appears to have been
the same substance and similarly used as our Touchstone. The French "
basané," swarthy, seems to have the same origin. This βάσανος is largely dwelt upon by Theophrastus (45-49). These were only found in the river Tmolus, were round and flat like a counter (ψήφος'), but twice as large as the largest counter ; and their upper side, that had lain exposed to the sun, was better for the touch than
the lower, whence a moisture was apt to exude. By means of this stone
the exact amount of alloy, either copper or silver, in the standard of
the gold stater could be exactly discovered. (See Lapis Lydius.)