transparent,
ranges from colorless (rare), to a light yellow, into yellowish-green,
then into deep yellow emerald-green. Sometimes an entire crystal has a
uniform green color, but generally one end is yellow and the other
green. Its hardness is on the prism faces, 6.5, and across them,
according to Doctor Smith, nearly that of the emerald; but a series of
experiments proved it to be somewhat less. At first considerable
difficulty was experienced in cutting it, owing to its remarkably
perfect prismatic cleavage, which is very lustrous. Gems have, however,
been cut up to 2 1/2 carats in weight. Specific gravity, 3.18 to 3.194.
The
yellow color exhibited by the mineral in even the darkest green gems
will prevent it from competing with the emerald, since it is this very
quality that has kept down the prices of the Siberian demantoids, or
Uralian emeralds, as the green garnets are variously termed. The finest
crystal of lithia-emerald ever found is in the Bement Collection. (See
Colored Plate, No. 5.) It measures 2 3/5 inches (68 millimeters) by 1/2 inch (14 millimeters) by 1/5 inch
(8 millimeters). One end is of very fine color, and would afford the
largest gem yet cut from this mineral, weighing perhaps 5 1/2 carats.
In Dr. Augustus G. Hamlin's cabinet is a fine gem weighing about 2
carats, and a cut stone of fine color and a good crystal are in the
collection of Col. W. A. Roebling. Dr. J. Lawrence Smith ' says that
the crystals, when cut and polished, resemble the emerald in lustre,
though the color is not so intense as in the finer variety of the
latter gem. Prof. Edward S. Dana says that, owing to its dichroism, it
has a peculiar brilliancy which is wanting in the true emerald. Thomas
T. Bouve, of Boston says: " One might infer from the statement made of
the greater brilliancy of both the hiddenite and garnet, when compared
with the emerald, that this should decide their relative beauty; but it
is not the case, for the emerald has a beauty of its own, in its deep
and rich shade of color, that will ever make it rank at least an equal
in loveliness with the newer aspirants for favor."* When the gem was
first introduced, it had a considerable sale because of its novelty as
an American gem and because of the newspaper notoriety it gained
through the controversy
1 Am. J. Sci. III., Vol. 21, p. 128, Feb., 1881.
5 Proc. Boston Soc. Nat. His., Vol. 23, p. 2, Jan. 2, 1884.
