192 A Book of Precious Stones
scarf pins. In coal-mining regions it is sold as souvenirs, mounted in medium to low-priced settings.
RUTILE
is oxide of titanium, containing more or less iron. When sufficiently
transparent and brilliant, its qualifications of hardness and
adamantine lustre make it a very desirable gem stone. The colour of
rutile is usually reddish brown, but some specimens when cut closely
resemble the ruby. Eutile sometimes forms hairlike crystals
penetrating quartz and other transparent minerals with a very curious
and beautiful effect.
SATIN
SPAR is a form of gypsum, white, with a delicately fibrous structure,
which, when polished, exhibits a beautiful silky lustre and pearly
opalescence. It appears in the jewelry trade sometimes in necklaces,
charms, and pendants. A great trade in these articles is a constant
source of revenue at Niagara Falls, tourists being ready purchasers on
the assumption that the mineral is native to the region; gypsum is
found at Niagara Falls but not of this variety; the raw material thus
used is obtained in Wales.
STAUROLITE occasionally appears among the stones handled in the trade. Colour, red-
