with a peculiar pearly shine, and sometimes it is iridescent. Specific gravity, 2.5 ; and softer than quartz.
In
commerce, adularia goes under various names, such as ^noon-stone,
sun-stone, girasol, fish-eye, and Ceylon or water opal. In the
moon-stone the color is white, with small bluish or greenish shades,
but the base is semi-transparent and milky; whereas the sun-stone
shows a yellow and reddish play of colors. Adularia is found in gangues
and' cavities of granite, gneiss, and limestone, and in pebbles
from Ceylon, Greenland, Bavaria, St. Gothard, Tyrol, Dauphine, and in
the United States,—particularly at Ticonderoga, near Lake Champlain,
New York, Maryland, Pennsylvania, Connecticut, and Massachusetts. The
adularia from St. Gothard is found in very large masses: I saw, in
1827, in the cabinet at Zurich, in Switzerland, groups of crystallized
adularia, measuring two feet in length and one foot in thickness, the
splendor of which dazzled my eyes.
Adularia,
displaying a good color, and strong pearly reflections, is now much
used in jewelry, for rings, pins, and other smaller ornaments.
Generally specimens which possess these qualities are cut out of large
lumps, then ground on a lead wheel, in cabochon form, and polished with
rotten-stone ; they are, in general, mounted in a black case, whence it
best shows its reflections. The moon-stone commands a good priee ;
exquisitely fine specimens, of the size of a bean, are worth from five
to ten dollars, and some of them were sold at Paris, of six lines
diameter, for seven hundred and five francs, and four lines for two
hundred and three francs.
The
largest moon-stone, in a brooch, three fourths of an inch in length, I
have seen, is in the possession of Francis Alger, Esq., of Boston; and
rough specimens, with most splendid reflections, I have admired in the
collection of the
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