GEMS AND PRECIOUS STONES. 51
TURQUOIS.
Crystalline
System—None, usually reniform, stalactitic, or incrusting. Hardness—6.
Specific gravity—2'6-2"8. Lustre—Inclining to waxy, feeble.
Composition—Hydrous phosphate of alumina, with a few per cent, of protoxide of copper. A1203, P203+5 H20.
Tubal: " One of them showed me a ring that he had of your daughter for a monkey." Shylock : " Out,
upon her! Thou torturest me, Tubal: it was my turquois; I had it of
Leah when I was a bachelor. I would not have given it for a wilderness
01 monkeys."
—Merchant of Venice, Act III, Scene 1.
This precious stone acquired its name from having been imported into Europe by way of Turkey.
The
turquois of commerce comes from Khorassan, in Persia, and it still
maintains its superiority, although the gem has been found in a great
many other localities, especially Mexico. In Persia it occurs in a
mountainous district, and is found in clay slate in veins traversing
the mountain in all directions. The best specimens from this locality
are noted for the delicate hue of the blue tinged with green, and the
faint translucency which they possess. The Shah of Persia has in his
possession some very fine turquoises, and he is accredited with taking
for himself all the finest specimens found in his dominions, the
inferior alone being permitted to leave the country.
These
gems are found in varying hues of blue and greenish-blue to
bluish-green, and the colour of those obtained from Persia is
permanent. Some years ago a variety was brought from Arabia, obtained
from near Mount Sinai, in red sandstone ; and, although of a finer blue
than the best Persian stones, it, unfortunately, did not keep its
colour, often changing its hue most rapidly. Some specimens have
retained their colour for a long time, but they can never become of
value because of this liability to change. Major MacDonald exhibited at
the London Exhibition of 1851 some very fine turquoises from this
locality, but all suffered by exposure to light, and one that was
purchased for a large sum of money had become by the end of a year
almost worthless, having faded to a great extent.
Some
fine specimens of turquois have been obtained from Mexico, and the
natives of that country were familiar with it, and used it in ancient
times long before the discovery of their country by Europeans. It is
obtained in New Mexico, and at Turquois Mount in Arizona. These gems
are greenish in hue, and were highly valued for ornamental purposes by
the original inhabitants. The mines were worked by the Spaniards 200
years ago, and many of the turquoises in the crown jewels of Spain were
found there. The workings at that time were very prolific, but the
water suddenly breaking in upon the Indians who were working in the
mine, drowned about one hundred of them. The destruction was so great
that the mine was abandoned, and remained closed until recently, when
the industry was re-established after being neglected for over 200
years.
In
Nevada, in the United States of America, fine blue specimens are found,
approaching those found in Persia, but they are of small size. Thibet,
China, Silesia, and Saxony are other localities where the turquois is
found. At one time it was supposed to come from Russia also, but this
appears to be erroneous, the idea most probably arising from the fact
that a large number are cut and polished at Moscow, obtained at the
fair of Nijni-Novgorod from Persian and Tartar merchants.
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