They are harder in
texture than those found in other parts of the world. Those brought from
Australia are nearly equal in hardness and brilliancy, while, so far as
our own experience goes, the Mexican often excel either in variety of
color and brilliancy; but it is not quite so hard as those from the
other two sources. This quality of hardness is one criterion of value in
precious stones, the diamond coming first, the ruby following it, and so
on. The author has seen an opal in Pesth weighing fourteen carats, for
which five thousand dollars were refused. They can be purchased at
Queretaro at from ten dollars to ten hundred; for the latter price a
really splendid gem may be had, emitting a grand display of prismatic
tints, and all aglow with fire. The natives, notwithstanding the seeming
abundance of the stones, hold very tenaciously to the valuation which
they first place upon them. Of course, really choice specimens are
always rare, and quickly disposed of. While the ancients considered the
opal a harbinger of good fortune to the possessor, it has been deemed in
our day to be exactly the reverse; and many lovers of the gem have
denied themselves the pleasure of wearing it from a secret superstition
as to its unlucky attributes. This fancy has been gradually dispelled,
and fashion now indorses the opal as being both beautiful and desirable.

Mexico also produces many other precious stones, among which are the
ruby, amethyst, topaz, garnet, pearl, agate, turquoise, and chalcedony,
besides onyx and many sorts of choice marbles.

On our route to the national capital we pass through a number of small
cities and towns, while we ascend and descend many varying grades.
Native women, here and there, bring _agua miel_, or fresh pulque, to us,
of which the passengers partake freely. It is a pleasant beverage when
first drawn from the plant, very much like new cider, and has no
intoxicating effect until fermentation takes place. As we progress
southward, occasional wayside shrines with a cross and a picture of the
Virgin are seen, before which a native woman is sometimes kneeling, but
never a man. Among other interesting places we come to Tula, which was
the capital city of the Toltecs more than twelve centuries ago. The
cathedral was erected by the invaders in 1553. The baptismal font in the
church is a piece of Toltec work. There is to be seen the yellow,
crumbling walls of a crude Spanish chapel, even older than the
cathedral