|
166 PRECIOUS STONES.
|
||
|
|
||
|
and
other precious Stones." " The true Topaz of the ancients is a
transparent Gem, of a diluted green colour that seems to have some
yellowness, or a Gold colour in it, very glorious." " It is reported to
be good against haemorrhages, and all manner of fluxes of blood, as
likewise to stop bleeding." This Topaz was afterwards called a
Chrysolite ; which name it still bears. The Topaz of the ancients was
quite a different stone.
Some
of the finest Topazes are almost colourless, and may be occasionally
mistaken for Diamonds ; but these stones are inferior in hardness, they
lack " fire," and become electric when heated. Such colourless Topazes
pass in England under the name of " minas novas." The coloured Topazes
are usually either yellow, or blue; the yellow is liable to suffer
bleaching by exposure to sunlight. In 1750 a Parisian jeweller
discovered that the yellow Topaz of Brazil, when subÂjected to a
moderate heat assumes a rose-pink colour ; and it is now generally
believed that all the pink Topazes occurring in jewelry owe their tint
to some such artificial treatment. To effect this purpose now-a-days
the stone is wrapped in German tinder, which is then ignited. The said
" burnt Topaz " is known to jewellers as Brazilian Ruby. In like manner
the blue Topaz passes under the name of Brazilian Sapphire ; and the
pale green as Aqua-marine ; a name strictly applicable only to the
sea-green Beryl. Occasionally the Topaz is found in Great Britain; but
simply in small crystals unfit for jewelry. St. Michael's Mount, in
Cornwall, has furnished specimens of such Topaz.
The Malachite Stone
(a variety of Topaz) is an ore of copper, which presents in its finer
varieties a beautiful green colour, thus leading to its use as an
ornamental
|
||
|
|
||