One of its constituents is titania, as is intimated by the name
of the species. Its color varieties afford green, yellow, gray,
brown, and black crystals, which exhibit a great difference of
forms, and strong refracting and dispersive powers ; it holds
a middle rank for hardness. Fine yellow specimens, yielding
beautiful gems, are obtained in Switzerland and other regions,
while black and brown varieties are plentiful in the United
States, but not of a quality suitable for the uses of jewelry.
In some of its varieties it resembles fire-opal.
Lepidolite. — Several countries of Europe, as well as some
localities in New England, afford this species of mineral,
which is frequently used for making ornamental boxes, vases,
and other fancy articles, and sometimes for personal ornaments,
though it is not, strictly speaking, a precious stone. The name,
meaning "scale stone," is due to its peculiar structure. It is
very soft, holding a rank of only two and one-half in the scale,
translucent, and is very complex in composition. The range
of colors includes white, rose, yellow, and different shades of
gray. The Indian lapidaries cut the crystals of lepidolite with
facets or en cabochon, which they sell for sapphires.
Cldorastrolite. — This name is composed of three Greek
words, signifying "green-star-stone." The mineral occurs in
small, rounded, water-worn pebbles which have come from trap,
on the shores of Isle Royale, Lake Superior, and is exclusively
an American gem. It is opaque, of a light bluish green color,
presents a stellated or chatoyant appearance, and, with a
hardness of five to six, takes a fine polish. It is sold for
cabinet use or gem-stones, the annual profits from this source
reaching, it is estimated, from two thousand to three thousand
dollars. Specimens one inch in length and of fine color have
been valued as high as fifty dollars each.
Axinite. — This substance is very rarely used in jewelry,
