ON THE RUBIES OF BURMA AND ASSOCIATED MINERALS. 
157 
bearing; for along this line are situated the principal mines where that gem is 
found—either in the hill-wash on the mountain sides and gullies, in the cavities 
of the crystalline limestone, and in the limestone itself, and in the alluvia of the 
rivers and streams. In all likelihood the ruby-bearing rocks extend further to the 
eastward ; but this region was not examined, owing to its lying outside of British 
territory, and being consequently a dangerous one to traverse. Although the distance 
from Thebayetkin to Mogok—the principal mining centre—in a straight line is not 
more than 34 miles, the distance by road, owing to its tortuous course up and down 
the mountain sides, is 58 miles. Part of this distance, as far as Kabein, is along 
a graded government road, while beyond to Mogok the remainder is over a straighter 
but more precipitous Burman pathway. 
From Mogok to the southward for some 15 miles the mountains of gneissic rocks 
gradually become less in height down to the valley of a large stream called Mobay- 
choung, which has deposited a wide spread of alluvial clays and gravels. The latter 
are extensively worked for rubellite by the natives, who say that no rubies are ever 
found in them. Near this the rocks are of a different character, and are either, so far 
as seen, mica schists, or a passage rock between schist and gneiss. 
The area of the ruby-bearing tract proper, as computed by Mr. Penrose, of the 
Government Survey of India, under the direction of Major Hobday, in 1888, is esti¬ 
mated at 45 square miles in extent; but, taking in the outlying districts, where old 
excavations were observed, he was of the opinion that this estimate should be 
increased to 66 square miles. In this latter area there is little doubt that he has 
included the rubellite mines of Nyoungouk. 
There is a small outlying tract of ruby-bearing rocks at Sagyin, 24 miles north of 
Mandalay and 8 miles from Maddeya, composed of crystalline limestone, forming low 
hills, rising from the alluvial plain of the Irrawaddy. 
Some 15 miles to the northward of Sagyin are two isolated limestone hills, named 
Nyoungwun and Bodaw, where it is reported by the natives that rubies have been 
found. 
It has been stated that, in making the railway from Rangoon to Mandalay, at 
Kyoukse, 30 miles from the latter place, an old working in limestone for rubies was 
discovered. 
The ruby-bearing rocks evidently extend over a large portion of Upper Burma on 
the eastern side of the Irrawaddy, and from thence into the Shan States. 
The sketch-map (fig. 1), illustrating the distribution of the gem-bearing localities 
of this part of Burma, has been compiled from the official map by Major Hobday 
and his assistants on the Topographical Survey of India. 
Before proceeding with the main portions of this paper, it is both a pleasure to me, 
and my duty also, to state that my investigations of the Burma Ruby Mines, 
described herein, could not have been completed in the time they were, had it not 
been for the invaluable assistance I received from the following gentlemen, viz. :— 
