The
gem topaz has been found in Huntington and Middle-town, Conn.;
Stoneham, Me.; North Chatham, N. H.; Sevier Lake, Utah; at Nathrop,
Chalk Mountain, Crystal Park, Florissant and Devil's Head Mountain,
Col.; and at Ruby Mountain, Nev. The first discovery of topaz in the
United States was that of Trumbull, Conn. Specimens of it, found there
in a vein of fluorite, associated with a chlorophane variety of
fluorite, were sent to Prof. Benjamin Silliman, who determined it to be
topaz. Six different determinations of its specific gravity gave
results varying from 3.42 to 3.47, with a mean of 3.45. In their
modification and color, the crystals afforded by this locality very
strikingly resemble those from Saxony, but are generally of larger
dimensions, and scarcely any of them would afford a gem, since they are
nearly all opaque. This same authority, in 1838, in a " Notice of a
Second Locality of Topaz in Connecticut," says; * " Among specimens
which I obtained at China Stone Quarry, in Middletown, two years ago, I
find one that contains above fifty crystals of topaz. They measure from
1/2 to 1/8 of an inch in length, are very slender and perfectly
transparent, being attached by a lateral plane to crystals of albite."
Probably the most beautiful and brilliant crystals of topaz known in
the United States are those found forty miles north of Sevier Lake,
Utah, and the same distance north of the town of Deseret on the Sevier
River. This locality, known as Thomas Mountain, is an isolated and arid
elevation about six miles long, and is described by Henry Engel-man,
geologist of the expedition that, under Capt. James Simpson, crossed
Utah in 1859. He found crystals loose on the surface. James E.
Clayton, of Salt Lake City, visited the place in June, 1884, and
obtained a large number of beautiful crystals, larger than those from
Nathrop, Col., and equally as brilliant as those from San Luis Potosi,
Mexico, which they closely resemble. Mr. Clayton states that still
larger crystals are found, and he says: " They are evidently not
secondary products, like zeolites, but primary, and produced by
sublimation or crystallization from presumably heated solutions,
contemporaneous, or nearly so, with the final consolidation of the
rocks."' Prof. J. Alden Smith refers
1 Am. J. Sci. I., Vol. 34, p. 329, Oct., 1838. * Am. J. Sci. III., Vol. 31, p. 432, June, 1886.
