THE RUBY MINES OF UPPER BURMA 363
tion
of stones above a certain size ; but it seems to be generally admitted
that few large stones were found, and of these a proportion, in spite
of severe punishments for concealment, never reached the King ; there
is no basis then for an estimate of the total revenue which he received
from the mines.
If
one may judge from the appearance of the rubies forming part of the
treasure taken at Mandalay, and which are now exhibited at the South
Kensington Museum, valuable stones were rare, as, except a few of the
smaller ones, none seem to be perfect.
As
is well known, recent accounts by experts have represented the
prospects of the mines in a much more favourable light, and the true
value will probably be ere long ascertained by the energetic operations
of a company conducted on scientific principles.
The
different kinds of precious stones found in the mines.— Although the
rubies have given their name to the mines, several other varieties of
corundum are also found, such as sapphires, oriental emeralds, oriental
amethyst, oriental topaz, and white sapphires ; and besides these there
are to be found spinels of various colours, hyacinth (or zircon),
iolite (or dichroite, a stone resembling sapphire), and lastly the
semi-precious rubellite, which is a variety of the mineral called
tourmaline, of which some exceptionally fine examples have been brought
from Ava, one of which has long held an honoured position in the
mineral collection of the British Museum.
According
to Mr. Spears, the proportion of sapphires to rubies was as 1 to 100,
but the former are often of large size and fine quality.
Pegu has been mentioned by some early writers l
as producing diamonds, but there are no real grounds for supposing
that either the diamond or true emerald occur in any part of Burma.
Mode
of occurrence and source of the gems.—Although it has for some time
been known that the rubies of Sagyin were derived from crystalline
limestones or marble, the source of the gems in the principal region at
Mogok, Kyatpyen, and Kathe was not actually ascertained till recently,
when these localities were visited by Mr. Barrington Brown. It was
known that they were for the most part actually obtained in derivative
gravels, and it had been inferred that the so-called clefts and lodes,
of a report which appeared before his examination, were really fissures
in limestones, where the stones had accumulated as the result of the
solution of limestone, and by gravitation into these recesses.
1 See Description, of the Diamond Mines of India, Phil. Trans., vol. xii, 1677, p. 907.
