of
crystalline form in these specimens. One rolled pebble weighs 3915
grams., another specimen weighs 8'2S6 grams., while a third weighs
17014 grams. These have an average specific gravity of 39095.
The
ruby has been made artificially by M. Fremy, of Paris, who succeeded in
manufacturing these gems of sufficient size to be used by watchmakers
for jewelling watches. I do not know the value of these artificial
rubies, or whether they can be made a financial success.
Sapphire or Oriental Sapphire.
Of
all the gem varieties of corundum the blue sapphire is perhaps the most
plentiful; yet, although found in good quantity in many parts of the
world, few large stones of good colour are obtainable. The value of the
sapphire does not increase in proportion to its size, as is the case
with the ruby, although large sums have been paid for specimens at
different times. The celebrated gem in the mineral collection of the
Jardin des Plantes, in Paris, weighs 133-1/16 carats, and is without a
fault. It was originally found in Bengal (India) by a poor man, came
into the possession of a German prince, and was by him sold to a French
jewel merchant for £6,800.
Two
fine stones were exhibited in the London Exhibition of 1862. The larger
weighed about 252 carats ; the smaller, and more beautiful one, was
brought from India, and after being recut weighed 165 carats. It is
supposed to be the most valuable sapphire in Europe, its estimated
value being £7,000 to £8,000.
Among
the historic sapphires (of which there are a great many) may be
mentioned the gem, cut in the form of a rose, once owned by Edward the
Confessor, and which now ornaments the Royal Crown of England. Another
fine sapphire in the same crown was purchased by George IV. It was
originally a sapphire ring taken from the finger of Queen Elizabeth
just after she expired, and was sent to James VI. of Scotland as a
token of his accession to the English throne.
Many of the treasuries of Europe possess very valuable sapphires, especially that of Russia.
The
value of a perfect sapphire of one carat is worth as much as a perfect
brilliant (diamond) of the same weight. To be perfect it must be of a
deep, rich blue colour by night as well as by day, because it is a
defect that the sapphire often has, of becoming an indifferent colour
by artificial light. The value of good stones is such, that in a
country like New South Wales, where sapphires are plentifully
distributed, some attention should be given to the collection of good,
clear, bright blue stones.
Engraved sapphires were at one time considered of the greatest value, a gem
in the collection of the Duke of Brunswick being engraved with the arms
of England, formerly belonged to Mary Queen of Scots. A sapphire
beautifully engraved with the crest and arms of Cardinal Wolsey has
been recently found in an old collection of jewels Iu the British
Museum there is a statue of Buddha cut from a single sapphire.
During
the Renaissance period engraved gems became fashionable, and many
engravings of white sapphire and white topaz were for a long time
considered as engraved diamonds. Occasionally sapphires may be made
colourless by heating them, and these white stones do acquire great
brilliancy, sufficient to deceive a casual observer. The differences
between these gems have been already stated in the article on the
diamond.
The blue stones that might be taken for sapphire are kyanite, iolite, blue tourmaline, and blue beryl.
Flickr
Stumbleupon
Scribd