of a more vivid color; the latter is harder, and likewise of greater specific gravity.
The Italian idocrase, which is cut at Naples, is mostly called the Italian chrysolite.
HAUYNE.
The
name of this mineral was given in honor of the celebrated French
mineralogist, the Abbe Hauy. It occurs in dodecahedral crystals, with
brilliant faces; also, in grains and massive; it has a conchoidal
fracture; is transparent and translucent; possesses a strong vitreous
lustre ; its structure is imperfectly foliated. Its colors are indigo,
sky, and smalt blue; also, white, green, gray, and black. It scratches
white glass and is scratched by quartz; white streak-powder; specific
gravity is 2.47. Before the blowpipe it loses its color and fuses into
a porous glass, and with borax into a diaphanous glass, which turns
yellow on cooling; it forms a jelly with acids. It consists of lime,
alumina, silex, protoxide of iron, sulphuric acid, and soda or potash.
It
is found in slacked basalt, and ejections of Mount Vesuvius ; on
Bodenmaise, on the Laach Lake, in Italy, and on the island of Tiree,
Scotland.
Hauyne
is not much known yet, but has lately been used for rings, ear-rings,
brooches, &c.; it is cut like idocrase, but the price will always
be high on account of its scarcity.
LAPIS LAZULI.
The
name of this mineral is derived from the Persian language, and means
blue color, or, with the Latin prefix, blue stone. The ancients were
well acquainted with it, and have employed it as a substitute for other
gems. The
