CRYSTALLUS. 119
and
only yielding to it in point of hardness. Although the refractive power
of the Crystal is but a third of that of the Diamond (being as 10.5 to
30), yet the Cinque-cento jewellers had found a way so to cut it into a
pyramid, that, when mounted in the favourite " tower-rings " of that
period, it presented the iridescence and much of the lustre of the gem
it was designed to counterfeit. De Laet mentions the having seen "
Cornish Diamonds " cut into " Tables " that could not be known from the
real gem.
Crystals
are sometimes found with a cavity in their substance containing a few
drops of water, which moves about as the stone is turned. This is
Pliny's Enhydros or Enhy-gros. "always perfectly spherical, colourless,
and polished, hut, when moved, something fluctuates about within it
like the liquid in an egg." This was regarded by the ancients as a most
wonderful miracle of nature, and an irresistible proof of the
correctness of the theory deducing its formation from hardened or
solidified ice. Claudian has left several elegant epigrams all turning
upon this idea :—
"
Pass not the shapeless lump of Crystal by. Nor view the icy mass with
careless eye ; All royal pomp its value far exceeds, And all the Pearls
the Red Sea's bosom breeds. This rough and unform'd stone, without a
grace, Midst rarest treasures holds the chiefost place."
" With th' Alpine ice, frost-harden'd into stone, First braved the sun, and as a jewel shone, Not all its substance could the gem assume— Some tell-tale drops still linger'd in its womb. Hence with augmented fame its wonders grow,
nd
charms the soul the stone's mysterious flow : Whilst stored within it,
from Creation's birth, The treasured waters add a doubled worth."
"Mark where extended a translucent vein Of brighter Crystal tracks the glistening plain :
