48 PRECIOUS STONES
one or more particulars to bring the possibilities of the market and his customers in accord.
Chief among the opaque, and by many esteemed above all precious stones, is the pearl.
A
lustrous skin free from blisters and blemishes, white and round,
constitutes a gem pearl. The faults to be avoided, as far as possible,
are a lack of sheen, blisters and indentations, dark and yellowish
tints, and irregularities of shape. There is also a dead, bony white
which is undesirable. This, however, is more liable to occur in
fresh-water pearls. A pear-shaped pearl should be rather long, of even
shape, and well pointed at the smaller end. An egg-shaped pearl must be
full and round at the larger end and well rounded also at the other.
Both ends should face up like a round pearl. Button pearls are less
expensive, and in many cases better than round for centres in clusters.
In all cases the sheen of the skin is of the first importance. The rule
heretofore laid down regarding colors applies also to fancy colored
pearls. A nondescript tint is a decided disadvantage, but a clean, rich
color enhances the value. Fresh-water pearls lack the soft, mellow
appearance of the Orientals, and it is said that both their lustre and
color are apt to fade after piercing.
The
body of the best opals is somewhat dense and milky, yet so constituted
that fiery lights of red, green, and blue flash through it with
distinct brilliancy. These colors should appear to best advantage when
the stone faces the eye, as the front appearance of the stone is of the
greatest importance. Red lights are more uncommon than orange or
yellow, and produce a much finer effect. The opal should not be shown
in a cross-light, but with the light coming over the shoulder of the
looker. A cross-light destroys the play of color. It should be
full-domed rather than flat, and the colors intermixed. Large, splashy
rays of color, if well diversified, are better than the small speckled
lights, but, to be gem, the
