most precious of all telluric productions; and it is clear that he was
acquainted with the true Indian diamond (although he mentions six
different sorts), for he described it as resembling rock-crystal in
transparency, and that the crystals terminated at both ends by a point
resembling two pyramids joined together, which description exactly
tallies with the octahedral form of the diamond; the hardness as very
great, so as to resist fracture on an anvil, and, in fact, breaking
both hammer and anvil before the diamond. He imagines it, however, to
become soft if immersed in goat's blood; and remarks that small pieces
were used by gem engravers, as at the present day. After the diamond
he values the pearl, and it is clear that he must have seen several
gems in their natural state, as he describes some of the crystals most
accurately. He however has clearly copied much from Aristotle,
Theophrastus, and Demo-critus, and he mentions many stones which are
either unknown to us, or are called by different names. He declaims
against the extravagance of the age, and especially against the
fashion of jewelled drinking-cups.
In the buried cities of Pompeii and Herculaneum, rings have been found with devices engraved on green jasper and chalcedony.
king of Mauritania/ was said to have had a statue, four cubits long,
made of one single piece of chrysolite, which he presented to Arsinoe,
the wife of Ptolemy.
The Romans, when they conquered Greece and