times used in jewellery and in cabinet work, but is not of any great value.
LABRADORITE, OR LABRADOR FELSPAR.
Although
not commonly used in jewellery, this stone is well known, and possesses
in some degree the brilliant multicoloured light-flashes of the opal.
It belongs to the triclinic system of crystallization, and is found
massive. Its hardness is 6; specific gravity, 2-67; lustre
vitreous (in one direction pearly); easily cleavable, and is usually
greyish in colour, sometimes nearly white. The chemical composition of
the variety from Labrador is, according to Klaproth—
