The
rubies are obtained in Siatn by the natives washing the alluvial
deposit that contains them. This washing is carried on in a most
primitive way with the dish. Large numbers of natives are thus employed.
I
am informed that at the locality where the rubies are obtained, the
formation is as follows :—Surface soil, 1 foot; under this a sandy
clay, from which the gems are obtained; then pure clay upon metamorphic
rock, overlying basalt. The majority of the stones are small, a large
one being rarely obtained. The rubies are plentiful. They are
principally used by watchmakers. The neighbouring hills are
principally an igneous rock, and there appears little duubt but that
this rock is the matrix of these gems.
The
hardness of the gem varieties of corundum is such that they are only
scratched by the diamond ; and partly for that reason an engraved ruby
was looked upon with admiration. At the London Exhibition of 1851 there
were two engraved rubies belonging to the Hope collection, one
representing the head of Jupiter-Serapis, the other a full length
figure of Minerva-Poliada. A good many other engraved rubies are
recorded, but some of these probably are not genuine.
The
ruby is cut by means of diamond powder on an iron wheel, and polished
on a copper one with tripoli and water. In the East, corundum wheels
are used for the cutting. The best stones are usually cut with facets,
but imperfect ones are cut en caboclion (see plate, " Eorms of
cutting precious stones"), that is, with a convex surface without
facets. The slippers of Chinese and Indian ladies are often ornamented
with rubies, cut en cabochon, and a large quantity were at one
time used to ornament the armour, scabbards, and harness, of nobles and
others in India and China. In fact, the ruby has always been highly
esteemed in Oriental countries, being regarded as endowed with more
than ordinary properties, even being laid beneath the foundation of
buildings, to secure good fortune to the structure.
In
New South "Wales a few rubies only have been obtained at the localities
given below, although no doubt a large number have been overlooked by
miners under the impression that they were garnets. Those found have
been small, and always in " drifts."
Considering
the importance and value of the ruby, it would be judicious in all
cases to ascertain the identity of red stones. The expression " better
be sure than sorry " is very apt.
The
importance of correct nomenclature in gems is well illustrated in the
case of the supposed rubies from South Australia. The finding of these garnets caused
some excitement at the time, although no mineralogist would consider
them anything but garnets. They are dark, deficient in hardness, fusible, and are not dichroic. There is an educational set of these garnets in the Museum collection.
The following are the localities in this Colony where rubies have been found:—
County Phillip.—Cudgegong River, Great Mullen Creek, Lawson's
Creek, Eats' Castle Creek, between Eumbi and Bimbijong.
,, Wellington.—Bald Hills, Mudgee.
„ Wynyard.—Tumberumba.
A
variety of the ruby, called Barklyite, has been found at Two-mile Flat,
Cudgegong, New South Wales, and by Mr. Porter, at New England.
The
specimens of this purple or magenta coloured opaque corundum in the
Museum collection, all came from the Ovens, in Victoria. The hardness
is a little less than 9, sapphire just scratching it. There is no
external signs
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