PRECIOUS STONES. 223
pearly. Heat readily causes it to fuse to a glassy mass. The specific gravity is 3-33
to 3'35; the hardness is 6-1/2 to 7. Little is known definitely about
its origin; it is said to be found in rolled masses in a clay of
reddish colour.
In chemical composition it is a sodium aluminium silicate, NaAl(Si03)2. The variety Chloromelanite is of a dark green colour and contains a good deal of iron.
The most important locality for Jadeite is in Upper Burma, on the River Uru, where it occurs massive in situ in
a dark serpentine, and also in boulders in the river below. Here it is
extensively mined, and thence much of it is sent to China, where, with
the other substance known as Jade, it is called Yu or Yu-shih. Some of
it is also sent to Mandalay, and there cut.
Jadeite is also said to occur in the Yarkand regions in situ, and it may very likely be found in situ in the Alps, as rough unworked fragments are found around the Lakes Neuchatel and Geneva, and it is said to occur in Alaska.
Ancient implements made of Jadeite are found very widely distributed in Europe, Asia, America and Africa.
It
is a highly prized mineral amongst the Chinese, who fashion it into
rings, vases, cups, and numerous other articles, displaying a skill and
patience in their work that is truly remarkable. Many prehistoric
weapons are wrought in this material, and the ancient Egyptians made
some of the scarabs of it. Good specimens still command a very high
price, especially in China.
The Amphibole Group.
This group, like the Pyroxene group, comprises several species of closely allied minerals, amongst which only two
