In
other words, opals are always cut as "cabochons", which is the
technical name for this shaping, because thus is their beauty best
brought out. This was the practice in the old days when Hungary was
practically the sole source of opals, and is the practice to-day when
many great opals come from the rich opal deposits of Australia.
The
Empress Josephine's great gem, "The Burning of Troy", came from the
mines of Hungary. Apart from the glorious play of light within its
depths its particular distinction is its size. It is the largest opal
ever mined, they say, being four inches long and two and a half deep,
and it belongs to the city of my birth. Even during the financial
straits of the post-war years, the Municipality of Vienna refused an
offer of £ 25,000 for the stone. You may think that to refuse
such a sum in time of unprecedented civic distress is an affair of
dog-in-the-manger-ish pride and stupidity, but after all, £25,000 would
not go far among a suffering population, large sum as it is for a bit
of stone; and, too, a great city of Vienna's history does not easily
surrender the vestiges of its glorious past without a struggle,
however far down in the world it may have come.
I
have seen it written with the pen of authority that the opal is so soft
a gem that it does not lend itself readily to the engraver's art. A
decade or so ago that was truer than it is now. But to-day the great
improvement in cutting and graving tools makes for a vast advance upon
the technique once available. At one time, for instance, I had through
my hands a fine opaline cup, rarely worked, which furnished me with
ample evidence that a master gem
