tin
wheel; and its last and best polish is received from the jewellers, by
rubbing with a linen rag and rouge. Since it is often traversed by
fissures and cracks in the interior, it requires great caution in
grinding. It is mostly cut in the form of cabochon ; also, as thick or
table stones, and is used for numerous purposes in jewelry, such as
rings, earÂrings, brooches, and also for mounting around the most
precious gems.
The
price of turquoise has, for the last ten years, much decreased; that of
an Oriental is generally four times higher than the occidental: one the
size of a pea is worth about five dollars; a good turquoise, sky-blue
and oval-cut, five lines long and four and a half lines broad, was sold
in France for two hundred and forty-one francs; and a light-blue,
greenish lustre, and oval-eut, five and a half lines long and five
broad, was sold for five hundred francs; whereas an occidental
turquoise, four lines long and three and a half broad, brought only one
hundred and twenty-one francs. Turquoise is very well imitated
artificially (so much so as to render it difficult to discover the
difference between that and the real), by adding to a precipitated
solution of copper and spirits of hartshorn, finely-powdered and
calcined ivory-black, and leaving the precipitate to itself for about a
week, at a moderate heat, and afterwards carefully drying the same, and
exposing to a gentle heat. This artificial turÂquoise is softer than
the real, and cuts with a knife in shavings, whereas the genuine yields
a white powder. The real turquoise displays in the daytime a sky-blue,
and at night a light and greenish color; is not attacked by acids, and
resists the fire.
In the museum of the Imperial Academy at Moscow, is a turquoise more than three inches in length and one inch in breadth.
A jeweller at Moscow is said to have had in his posses-
