in practice the simple tests recommended before purchasing, as few persons even in the trade are aware of the difference.
A
large mass of white topaz in one of the cases of the British Museum was
many years ago used as a door-weight by a marine store-dealer in
London; he afterwards sold the same for three shillings. It weighs
about 12 1b. avoirdupois.
It
is supposed that the word topaz is derived from the island Topazion, in
the Red Sea, whence the Greeks obtained a yellow stone; it is, however,
doubtful whether the topazion signified what we call topaz ; but there
is no doubt that this stone was known in very early times. Formed of
this there are still in existence several intaglios of very early Greek
workmanship. It is also one of the stones mentioned in the Bible; in
the Middle Ages it was considered typical of St. James the Less, the
Apostle. The large so-called diamond in the Portuguese treasury is
supposed to be a white topaz; it is rather larger than a hen's egg, and
weighs 1680 carats.
The
following properties were ascribed to the topaz by the ancients:—It
discovered poison by becoming obscured when in contact with it; it
quenched the heat of boiling water, and its powers increased and
decreased with the increase and decrease of the moon ; it calmed the
passions, and prevented bad dreams.
The Emperor Hadrian is reputed to have possessed a topaz seal ring engraved with these lines :—