The
Ceylon variety ought only to be called Oriental moonstone, from the
peculiarity that it is more uniform, not striated like that from St.
Gothard, and having also a brighter lustre; its chatoyant qualities are
therefore more prominent.
Sun-stone contains minute scales of mica, and reflects a pinchbeck-brown tint.
•
COMMON FELSPAR.
This
felspar occurs in crystals, massive, and disseminated ; its fracture is
uneven and splintery; is translucent; has a pearly and vitreous lustre;
its colors are white, gray, red, yellow, and green, in their various
shades, sometimes with a variegated bluish, greenish, or reddish play
of colors; its texture is compact, or minutely foliated.
The
amazon-stone, or green felspar, is from Siberia; likewise splendid
grass-green felspar has been found in the United States, at
Southbridge and Hingham, Massachusetts, and Cow Bay, New York;
of apple-green color, at Topsham, and near Baltimore, Maryland. Also,
the American glassy or vitreous felspar, found in Delaware, which ought
properly to be quoted as a distinct species, is arranged with this
variety.
Felspar is widely diffused all over the globe, and with a few exceptions
is more common than any other mineral; it forms a constituent part of
most primitive rocks, such as gneiss, granite, &c.; is the
principal ingredient of the sienites, porphyry, and, in fact, with a
small percentage of other minerals, forms whole mountain ranges and
chains in various parts of the globe: such we see in Siberia, the north
and west of Scotland, &c, all of which are surrounded by
felspar. Immense beds exist in the United States: around Wilmington, in
the State of Delaware, is an inexhaustible deposit of exquisite and
perfectly pure felspar; and in
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