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186 GEMS AND PRECIOUS STONES IN THE
The
serpentine of St. Lawrence County, N. Y., also that of Cornwall,
Monroe, and Warwick, Orange County, N. Y., the ophiolite of New York
City and vicinity, the serpentine of New Rochelle, N. Y., also some of
the Hoboken, N. J., and the Staten Island varieties are useful for
ornamental and decorative purposes.
On
Deer Island, Me., serpentine of a very light-green color occurs. The
serpentine from the neighborhood of Patterson, Caldwell County, N. C,
is of a dark greenish-black color, and admits of a fine polish.1
In several localities in Delaware County, Pa., it occurs in combination
with calcite. Serpentine is quarried chiefly in three places, Roxbury,
Vt.; Moriah, Essex County, N. Y.; and Dublin, Harford County, Md. The
Vermont stone is deep green in color, traversed by white veins of
calcite, and takes a beautiful polish. It compares very favorably with
the Italian verde antique or verde di Prato, from the quarries in
Tuscany. The Moriah stone, which is similar in color, but granular in
texture, and spotted rather than veined, is found in the market in the
form of mantels, table-tops, ornaments, and similar objects. The
Maryland stone is more uniformly green in color than either of the
others, and contains very little calcareous matter. It is within easy
reach of Baltimore. According to Prof. Genth, who reported on this
locality in 1875, it consists of a very large bed of green serpentine,
about 500 feet in thickness, overlying a bed of black mottled
serpentine about 800 feet in thickness; in the latter, masses of the
green serpentine are frequently found imbedded. Beneath this immense
bed of serpentine is a smaller bed of green serpentine, 180 feet in
thickness, and beneath this, there is a third bed of green serpentine.
Of its quality, he says: " Everywhere it shows exactly the same
character, but, as should be expected, that which came from a greater
depth showed a somewhat lighter color and greater compactness." He
concludes that beyond doubt there is an inexhaustible quantity of this
green serpentine in the most favorable position for mining on a large
scale, and with an abundant water-power to manufacture it into
marketable forms. A coarse serpentine, used for building purposes, but
not suited for ornamental work, is quarried in considerable quantities
in Chester County, Pa. The stone is dull green
1 Minerals of North Carolina, p. 57.
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