280 NATURAL HISTORY OF PRECIOUS STONES, &c.
illuminated
with a certain oily lustre ;" or the rhetorician's (appended to Mai's
Symmachus) description of them in the jewels of the Imperial bride, as
"playing with a quivering green" (so distinctive a character of the
true stone) ; can any one longer doubt that the Romans were acquainted
with the true Emerald, or suppose that they could have applied such
terms of praise to the dull Plasma or opaque Malachite, which so many
archaeologists have contended were alone understood by the name
Smaragdus ?
It cannot, however, be denied that the
of the
earlier
Greeks signified any kind of green stone that was brighter and more
transparent than their Jaspis (our Plasma). In no other way is it
possible to understand Theophrastus (23) : " Of stones used for
signets, some for
the sake of their beauty......the Smaragdus possesses
also
some peculiar properties, for it assimilates the colour of the water
into which it is thrown to its own colour—the stone of middling quality
tinging a smaller quantity ; the best sort all the water ; whilst the
worst only colours the liquid directly over and opposite to itself."
(Meaning that it will give a greenish cast to the water by the reflection of its own colour, not by staining the liquid as most readers absurdly understand the passage. But this test is not now to
be confirmed by experiment.)* " It is also good for the eyes : on which
account people wear ring-stones made of it, for the sake of looking at
them. But it is rare and small in size, unless we choose to believe the
stories about the Egyptian kings ; for some assert that
