PRECIOUS STONES. 583
ductions of this locality exceeded in quality and size anything yet obtained.
Fluorite.—About
four years ago a small vein of fluorite was discovered in the Archaean
limestones in the town of Macomb, Saint Lawrence county, New York. It
was worked irregularly from time to time until last summer, when the
vein suddenly widened, breaking through into an opening or cavity 22
feet in length and varying in width from 8 to 18 feet. The top, bottom,
and sides were lined with a magnificent sheet of crystals, varying from
1 to 6 inches in diameter, and each in turn forming part of larger
composite crystals. Between the floor and the walls was a layer of
partly-decomposed calcite, which was readily removed, so that groups of
crystals weighing from 10 to several hundred pounds each, and one of
them measuring 2 by 3 feet, were easily detached. The cavity contained
at least 15 tons of fluorite. The habit of the crystals is, in nearly
every instance, that of the simple cube, but slightly-developed faces
of the octahedron are often present. Almost all the crystals have on
the surface a small, botryoidal elevation, an even coating of brown
hydrodolomite, which is readily removed with diluted hydrochloric acid.
The crystals are well colored, but the surfaces are dull. The fluorite
is of a uniform light sea-green color, except where it is attached to
the gangue, or at the junction of the crystals. Here there are small
spots of a rich emerald-green from 1 to 2 inches in diameter. This find
is strikingly like that of the famous Muscallonge lake localities of
forty years ago, except that the crystals are of a finer color and
occur in larger groups. The occurrence of a second deposit in this
county leads the hope that fluorite may exist here in commercial
quantity available for the arts.
Amber.—For
the last fifteen or twenty years travelers have occasionally brought
specimens of a remarkable amber from some locality in southern Mexico.
The information that has been gained concerning it is brought to the
coast by natives, who say that it occurs in the interior so
plentifully as to be used by them for making fires. The color of this
amber is a rich golden yellow, and when viewed in different positions
it exhibits a remarkable fluorescence, similar to that of uranine when
dissolved in water, which it also resembles in color. A specimen now
in the possession of Mr. M. T. Lynde, of Brooklyn, New York, measures 4
by 3 by 2 inches, is perfectly transparent, and is even more beautiful
than the famous so-called opalescent or green amber found in Catania,
Sicily. This material would be extremely valuable for use in the arts.
It is believed that an expedition has started for the locality in the
interior where it is found.
New developments in foreign localities.—The
Burmese ruby mines were leased to a powerful London syndicate in
November, and machinery was immediately sent to Mandelay, Burmah, for
the purpose of prospecting and working the mines. From all appearances
active explorations will take place during 1889, and within a short
time it will be definitely known whether or not these mines are
exhausted.
