under that impression. The following will serve to illustrate the
advantage of being able to determine these gems : A large mass of white
topaz, now in the British Museum collection, was at one time used as a
door-stop by a marine store dealer in London. He sold it for 3s. It
weighs 12 lb. avoirdupois.
has been stated that the topazes taken from the beds of the rivers at
Capao, in Brazil, secured a net profit of £3,000 in twelve years.
present the commercial value of the topaz is small. A stone of good
size and of good colour may be purchased for a pound or two, while
smaller stones, in the rough, are only worth a few shillings per pound
avoirdupois ; still they are of some value, and worthy of collection,
especially in the New England District of New South Wales, where they
are plentifully distributed. Good pink stones (which, of course, are
manufactured from topazes having a suitable colour) are worth from
about £2 per ounce. In some parts of India the topaz is of far greater
value than in England.
describes a topaz, weighing 157 carats, belonging to the Emperor
Aurungzeb, an Indian monarch, which had been purchased by him for the
large sum of £18,000. This might hare been an " Oriental topaz."
these gems were of far more value, but fashions change and tastes
differ; and gem stones, being used principally for ornamental
purposes, are entirely at the mercy of fickle fancy.
topaz has been occasionally used by the engraver, even from very early
times, intaglios being in existence of early Greek workmanship. An
antique engraving, bearing a cluster of stars, in the St. Petersburg
collection ; the portraits of Phillip II. and Don Carlos, engraved on
a topaz, in the Royal Library of Paris ; and the engraved seal ring
owned by the Emperor Hadrian, are among the few engraved specimens of
this gem. It does not appear to have been generally in favour for work
of this class.
is cut on a leaden wheel with emery, and polished with tripoli powder.
The best form of cutting is as a " brilliant " having the table smaller
than in the diamond. The large so-called diamond in the Portuguese
Treasury is supposed to be a topaz ; it is as large as a hen's egg.
topaz is found in almost every part of the world, and in Saxony
constitutes massive rocks, known as " topaz fels." Often this gem is
associated with granite and gneiss, and usually some fluorine is
contained in these rocks. In the Urals it is found in granite. In
Brazil it is found in a loose sandy clay. Some beautiful blue specimens
have been found in Colorado, in the United States ; pale violet in
Saxony ; sea-green, sometimes known as aquamarine, in Bohemia; blue in
Scotland; while Brazilian specimens are found of nearly all colours.
topaz is, when crystallized, found as rhombic prisms, usually having
but one end regularly terminated. When thus seen it cannot be mistaken
for quartz, which crystallizes in the hexagonal system ; nor for the
yellow sapphire, which is also hexagonal. This difference in
crystalline form, together with the perfect basal cleavage of topaz,
and difference in hardness, are usually quite sufficient to determine the topaz; even in waterworn pebbles a flat portion is usually seen where the topaz has cleaved.
fine topazes occur in the southern portion of the Urals, in the Ilmen
Hills. They are also found in the Mourzinsk deposits in the north-east
of Ekaterinburg. The largest topaz known was found here. It is now in
the museum of the Mining Institute. It measures 27 centimetres (about
10-1/2 inches) in length, and 31 centimetres (about 12 inches) in
topaz is common in New South Wales, especially in localities where tin
is obtained, and specimens have been found of large size, especially
those from near Mudgee.