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ever,
when it occurs in large pieces which exhibit a play of colors that ' it
is prized as an ornamental stone. The labradorite exhibiting the latter
property in the most remarkable degree and hence most valued is that
found on the coast of Labrador near Nain, and the adjacent Island of
St. Paul. It was first found here by a Moravian missionary named Wolfe,
and brought to Europe in the year 1775. It occurs together with
hy-persthene, in a coarse-grained granite, or perhaps a gneiss. From
these it is weathered out by wave and atmospheric action, and occurs as
beach pebbles. It is also mined from veins. Labradorite of pleasing
color and opalescence occurs in a few localities in Canada, and in
Essex County, New York. Two localities occur in Russia, one near St.
Petersburg, and the other in the region of Kiew. The labradorite of the
latter locality is the better, its occurrence being in a coarse-grained
gabbro. The Labrador occurrence exceeds all others, however, in
abundance and beauty, and by far the larger quantity used in the arts
comes from there. The play of colors which gives labradorite its
attractiveness is rarely seen to advantage except upon a polished
surface, but whether polished or unpolished, it only appears when the
surface is held at a particular angle with reference to the eye.
Emerson thus describes it in his essay on " Experience," " A man is
like a bit of Labrador spar, which has no luster as you turn it in your
hand, until you come to a particular angle; then it shows deep and
beautiful colors."
The
play of colors seen in labradorite is not like that of the opal, which
presents to the eye fragments of different colors varying in different
positions, but appears as broad surfaces of a single color. It is only
rarely that these colors change with a change of position. The colors
over any given surface are not usually alike, but more than two or
three tints are rare. Each tint is uniform where it occurs, but a
tinted surface may be interspersed with many spots exhibiting no sheen.
Both colored and uncolored portions have only vague outlines, and merge
into each other at the edges. Bauer mentions a labradorite from Russia
the colored portions of which formed a striking likeness of Louis
XVI., the head being a beautiful blue against a gold-green background,
while above appears a beautiful garnet-red crown. Excellent effects are
sometimes produced in labradorite by cutting it in the form of cameos
so as to make the base of different color from the figure in relief.
Because of its chatoyancy labradorite is sometimes known as " ox-eye,"
or " oeil-de-boeuf." Of the different colors shown by
labradorite blue and green are most common, yellow and red least so.
These colors are regarded by Vogelsang as of different origin, the blue
being, in his opinion, a polarization phenomenon due to the lamellar
structure of the feldspar, and the
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