2
inches long, while a few were observed 3/5 inch (15 millimeters) in
width and 2/5 inch (10 millimeters) in thickness. Occurring in white
quartz, they form beautiful specimens, and the loose crystals were
extensively sold for sapphire at Roane Mountain, the summer resort.
Some gems have been cut, and a fine example is in the United States
National Museum. It is, however, too soft to admit of much wear.
Datolite,
in compact, opaque, white, creamy, and flesh-colored varieties, found
at the Minnesota, Quincy, Marquette, Ash-bed, and other mines in the
copper region of Lake Superior, admits of a very high polish, and
makes an excellent opaque gem or ornamental stone. One especially fine
nodule over 4 inches across, with a flesh-colored centre shading off
into gray and creamy tints, found at the Delaware Mine, is in the
cabinet of Clarence S. Bement. Some fine specimens of this mineral are
also in the William S. Vaux Cabinet at the Academy of Natural Sciences
in Philadelphia.
The staurolites of Fannin County, Ga., first described by •
Prof. Edward S. Dana,1
are found twelve miles southeast of Ducktown, Tenn., a locality which
has furnished some of the finest known twinnings of this mineral. From
their resemblance to a cross, these staurolites have found sale abroad
as ornaments and charms, and are as highly regarded as those that are
found in Brittany, France, which, according to the legend, were
supposed to have been dropped from heaven. The Fannin County
staurolites occur twinned in single and double crosses, and are found
in large quantities in a decomposed rock of mica schist. Of those taken
out, perhaps one-tenth are perfect crystals. They all require a
certain amount of scraping and cleaning. Brilliant crystals are found
at Windham, Me., some of the twins forming fine crosses. Occasionally,
transparent crystals are found here that if cut would afford
mineralogical gems resembling poor garnets. Staurolite is also found at
Fran-conia and Lisbon, N. H., in mica slate; on the shores of Mill
Pond, loose in the soil; at Grantham, N. H.; at Cabot, Vt.; at
Chesterfield, Mass.; at Bolton, Litchfield, Stafford, Tolland, and
Vernon, Conn.; on the Wissahickon, eight miles from Philadel-
1 Am. J. Sci., III., Vol. 11, p. 385, May, 1876.
