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I See an Opal
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effect is produced by the white ray which in good specimens divides the stone into two equal parts.
The
mineralogists class it among the quartzes, and further enlighten us by
saying that it is a variety of chrysoberyl. If this does not convey
much to the layman there are other facts concerning the gem which are
better worth remembering. Cat's-eyes are exceedingly hard stones,
inferior in that respect only to diamonds and sapphires. They are very
lustrous too, and when an experienced cutter has made the most of a
good piece of material the rayed edges are so bright that they appear
double.
Cat's-eyes
are said to be found exclusively in two localities, Brazil and Ceylon,
and they are comparatively rare even there. The largest cat's-eye ever
found was of the size of a hazelnut. I have seen and handled specimens
covering the full range of colours in which this attractive material is
supposed to occur. I have in my time been charmed by the light green
variety with golden gloss, bisected by the white streak which, owing to
refraction, appears to move as one turns the stone in one's hand; I
have also been enamoured of the dark green cat's-eye divided by the
same inescapable white band, and have been likewise intrigued by the
dull syrupy cat's-eye, almost honey coloured, across whose domed face
the single or double streak of white crosses like a bar of candied
sugar imprisoned in the stone. And I have seen the rarest cat's-eye of
all, the perfect black with the white centre ray in strongest contrast.
If a certain Hatton Garden kerb dealer had taken the
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