UC-NRLF B 14

3 2 GEMS AND PRECIOUS STONES.
The famous spinel in the Royal Crown of England, once thought to have
been a ruby, was known to the Black Prince ; it came into his possession,
and was afterwards worn by Henry V at Agincourt; it is thus of some
historic importance, although its intrinsic value has become lessened by its
real composition having been discovered. The knowledge that so many of
the historic rubies are simply spinels, casts grave doubts as to whether many
other large stones still supposed to be rubies are not spinels.
To illustrate the necessity of correct nomenclature in reference to these
gems, the recent history of a fine blue spinel is worth repeating.
It was an
Indian-cut stone, forwarded to London from that country as a sapphire ; it
was recut in London and sold as a sapphire found to be
;
it was subsequently
a spinel, and was returned by the purchaser to the merchant from whom he
bought it. This stone weighed after recutting 25 carats. Mr. Streeter
mentions two fine spinels that were exhibited in the London Exhibition of
1862, one of perfect colour and free from flaws weighed 197 carats ; when
recut in London it weighed 81 carats, and was then a "perfect stone." The
other weighed 102| carats and when recut weighed 721 carats.
Most of the large spinels come from India, certainly from the East, and one
of Oude it was of the size of a
of the finest recorded belonged to the King ;
pigeon's egg, and had great lustre. Besides India, spinels fit for jewellery
come from Burmah, Siam, Ceylon, and the United States of America.
The red varieties of the spinel known as "spinel ruby" and "balas ruby"
the stones bearing the latter name are inferior
have little to distinguish them ;
in colour and brilliancy to the former, and less like the true ruby. The
origin of the term " balas " has become quite a debatable question ; many
theories have been put forward by different writers, but it is unnecessary to
notice them it is sufficient that the name ; distinguishes the stone.
The Persians have a tradition that the mines from which these gems are
obtained were discovered through the mountain being divided by an earthquake,
and that they were mistaken for the true rubies. There are famous
mines at Badakhshan in Tartary, where balas rubies are found, and the
natives of this district have a superstition that two large stones always lie
near each other, and when one is found they most diligently search for the
other ; and it is stated that, if unable to find it, they will even break the
stone found in order to keep up the belief.
The natives of India call the spinel Lai Eumani, and ascribe to it valuable
medicinal properties.
Spinels occur embedded in granular limestone, and with calcite in
serpentine, gneiss, and allied rocks. It is also found in the cavities of masses
ejected from some volcanoes, for instance, the ancient ejected masses of
Mount Somma. They also largely occur as water-worn pebbles in the beds
of rivers, and alluvial deposits of many localities. A few good stones of
small size have been found in California. A pale blue spinel is found in
Sweden, embedded in limestone. Green spinels are found in slate in the
Ural Mountains. Jn Bohemia small rose-red crystals occur with pyrites.
Spinel, as has been stated, crystallizes in the cubical system, and its principal
form is the octahedron, sometimes showing faces of the rhombic dodecahedron,
it is also found as twins, the twinning taking place parallel
to one face of the
octahedron. Some of the email crystals are so perfect, and of such a good
lustre, that they might be used for the purpose of ornamentation in their
natural state. Their form of crystallization readily distinguishes them from
the ruby the other differences ;
have already been pointed out.
Erom garnets, they may be distinguished by being infusible, garnets fusing
easily in thin splinters in the blowpipe flame. Both these minerals crystallizing
in the cubical system, their optical properties cannot be used to dis-