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Spinel and Balas.
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the
one hides it until he has found a twin stone ; failing this, they are
said to break the large one in order to keep up the superstition.
Spinels
are found in Australia, especially in New South Wales where they are by
no means uncommon in auriferous deposits, as on the Cudgegong, Peel,
Macquarie, Severn and other rivers, where gem-stones are found as
rolled pebbles in the gravels, or drifts.
The Balas or Balais Ruby,
is a dark variety of Spinel, with a tinge of blue appearing at the
angles of the octahedron, which gives it a milky kind of shimmer. The
colour is probably due to chromic acid. The name "Balas" or " Balaksh "
applied to this stone, is said to be a corruption of Badakshan, one of
the localities which, as stated above, yields the Spinel.
Pleonaste is an opaque black variety, which was called Ceylonite, by
Rome de l'Isle, who analyzed it, with a number of other crystals
brought from Ceylon. It was Haüy who, seeing its form resembled that of
the Spinel, desired to give it a special position in his system of
minerals, and named it Pleonaste, which signifies superfluity. Further investigation showed that it was .in reality a black Spinel.
A black iron-spinel, known as Hercynite, occurs in the form of rolled crystals as a frequent companion to the Sapphires of Siam, and is termed by the gem-diggers nin.
SPINEL.
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