146 THE CURIOUS LORE OF PRECIOUS STONES
cisive argument against identifying the opalus with an opal, for it is well known that no stone is more difficult to imitate.
About
the middle of the eighteenth century, a peasant found a brilliant
precious stone in some old ruins at Alexandria, Egypt. This stone was
set in a ring. It was as large as a hazel-nut and is said to have been
an opal cut en cabochon. According to the report, it was
eventually taken to Constantinople, where it was estimated to be worth
"several thousand ducats."6 The description given of this
gem, its apparent antiquity, and the high value set upon it have
contributed to induce many to conjecture that it was the celebrated
"opal of Nonius." Of course this was nothing but a romantic fancy. It
is also quite certain that an opal would scarcely hold its play of
color or compactness for twenty centuries, for most opals lose their
water—slowly perhaps, but surely— within a lesser space of time. Even
the finest Hungarian opals show some loss of life and color within a
century or even less, and some transparent Mexican opals lose their
color and are filled with flaws within a few years' time.
The
Edda tells of a sacred stone called the yarkastein, which the clever
smith Volondr (the Scandinavian Vulcan) formed from the eyes of
children. Grimm conjectures that this name designates a round,
milk-white opal. Certainly the opal was often called ophthalmios, or
eye-stone, in the Middle Ages, and it was a common idea that the image
of a boy or girl could be seen in the pupil of the eye.
Albertus Magnus describes under the name orphanus
* Hesselquist, " Voyages and Travels in the Levant," English trans., London, 1766, pp. 273, 274.
