hitherto
known of their kiud in beauty and size, selling from 50 cents to $100
each, in a few exceptional cases $150. Those displaying the chatoyant white and the opalescent blue color are especially beautiful.
The
demand for the cat's-eye also brought into demand the then rare mineral
from the Orange river, South Africa, known as crocidolite, more
especially that variety that has been altered to a quartz cat's-eye. In
this stone an infiltration of siliceous material coated each fiber with
quartz or chalcedony, giving it the hardness of 7. This pleasing stoue
readily sold for $6 a carat, and at the outset for even more; but owing
to the excessive competition of two rival dealers, who sent whole
cargoes of it to the London market, the price fell to $1, or eveu to
25 cents per pound in large quantity. Even table tops have been made of
this material by veneering. Vases, cane heads, paper weights, seals,
charms, etc., were made of it and sold in large quantities. Burning it
produced a bronze-like luster, and by dissolving out the brown oxide of
iron coloring au almost white substance was obtained, which was dyed
by allowing it to absorb red, green, and brown colored solutions.
These, owing to the delicacy of the fibers, were evenly absorbed. Ten
years ago this material was practically unknown, but so extensively has
it been sold that to day it is to be found at every tourist's stand,
whether on the Eigi, on Pike's Peak, in Florida, at Los Angeles, or at
Nishni Novgorod, showing how thoroughly organized is the system of
distribution in the gem market. The green quartz cat's-eye from Hof,
Bavaria, has also been brought into use and quite extensively sold, but
at present both these varieties are ouly used in the very cheapest
jewelry.
Since
it has become generally known that Queen Victoria is partial to the
opal, the old and stubborn superstition concerning it, which is said to
date from Scott's "Anne of Geierstein," has been slowly yielding,
until now the gem has its share of public favor. During the last two
years ten times as many opals have been imported as were brought here
during the preceding decade, many of these being the fine Hungarian
stones. Mexican fire opals are much more common, as those tourists
know to their sorrow who buy these stones at exorbitant prices in
Mexico, hoping thus to pay the expenses of the trip, until they find on
reaching New York that they are worth only about a quarter of what they
paid for them.
The
opal mines of Mexico are situated on the Hacienda Esperenza, near
Queretaro. It is believed that a demand of 50,000 stones per annum
could be supplied without raising the price perceptibly.
The
opal mines of Dubreck, Hungary, yield the Government a revenue of
$6,000 annually. The output is so carefully regulated that the market
is never glutted.
About
ten years ago a new and very interesting variety of opal was brought
from the Baricoo river, Queensland, Australia, where it was found in a
highly ferruginous jasper-like matrix, sometimes apparently as a nodule
and then again in brilliant colored patches, or in specks
