|
174 PRECIOUS STONES
3.5;
etc. Fuses to a white glass. The principal color is azure-blue; this is
often modified by green and yellow tints, and it is sometimes red.
Found in Persia, China, Siberia, Bucharia, and South America.
Lazulite,
supposed at first to be lapis lazuli, is found at Salzburg, in Styria,
in North Carolina, and Georgia. It occurs in dark-blue crystals and
crystalline masses; rarely in oblique crystals. Hardness, 5 to 6,
brittle; specific gravity, 3.1. Lustre vitreous; opaque. Composition:
phosphoric acid, 41.8; alumina, 35.7; magnesia, 9.3; water, and ferrous
oxide. It swells under the blow-pipe, but does not fuse. Color, fine
azure-blue.
Lepidolite
occurs in the Urals, Moravia, and in Connecticut, Massachusetts, and
Maine, United States, in purplish crystals and massive. It is a lithia
mica, containing about three per cent, lithia. Color, lavender to
heliotrope.
Lintonite is a variety of prehnite.
Lodestone
is the iron oxide possessing magnetic qualities. This ore was called
magnes, from Magnesia, a province of ancient Lydia, where it was found.
Our words magnet and magnetism were derived from this source.
Microlite
is found in Virginia. Hardness, 6; specific gravity, nearly 6.
Transparent to opaque. Consists of tantalum oxide, 86; lime, 12; and
other oxides, etc. Color, hyacinth-red to yellow.
Moroxite is a bluish-green variety of apatite.
Natrolite is named from natron, soda.
It is a limpid white mineral, the crystals of which are too small to
cut for gems. Crystallization trimetric, in right rhombic prisms
terminated by a short pyramid. Hardness, 4.5 to 5.5, and brittle;
specific gravity, 2.14 to 2.23. Cleavage perfect parallel with lateral
planes.' Lustre vitreous; transparent to translucent. Consists of
silica, 47.4; alumina, 26.9; soda, 16.2; water, 9.5. It becomes opaque
and fuses to a glass bead before the blow-pipe, and forms a thick jelly
with acids be-
|
||
|
|
||