CHRYSOLITE. BASALT. 95 
CHRYSOLITE FAMILY. 
137. CHRYSOLITE, or PERIDOT, is a soft gem, 
usually of yellowish green colour, though sometimes it is 
grass-green, or bluish green, but with a tinge of brazen. 
It in generally found in fragments and rounded pieces, and 
rarely crystallized. In the latter case its regular form is an 
eight, ten, or twelve-sided prism. 
Though scarcely harder than glass, and consequently 
inferior to most other gems in lustre, these stones are 
not unfrequently used in jewellery, particularly for 
necklaces and ornaments for the hair ; and, when well 
patched in colour, and properly polished, their effect 
is very good. They are, however, too soft for ring 
stones ; for, by wearing, they soon become dull on the 
surface. But it is said that their lustre may, in some 
degree, be restored by immersing them in olive oil. 
To give the greatest brilliancy to this stone, we are 
informed by Mr. Mawe, that a copper wheel is used, 
on which a little sulphuric acid, or spirit of vitriol (24), 
is dropped ; and that, during the process, an highly 
suffocating odour is given out. But he is of opinion 
that the most Advantageous way of working it would be 
that in which glass is cut. 
Chrysolite is imported from the Levant, and is said 
to be found in Upper Egypt, and on the shores of the 
lied Sea. 
BASALT FAMILY. 
138. BASALT is a greyish black and coarse grained stone? 
which is usually found either in globular distinct pieces or in 
groups of large columns, each of which has from three to eight 
sides, and is divided horizontally into numerous stones, that 
very exactly lie upon, or Jit into each other. 
The most remarkable assemblages of basaltic co- 
lumns that are known are those called the Giants* Cause- 
way, on the coast of Antrim, in Ireland, and the Cave 
ofFingal, in the island of StafFa, one of the Hebrides, 
or Western Islands of Scotland. 
