ON THE RUBIES OF BURMA AND ASSOCIATED MINERALS. 
189 
the rock may be cut out and burned in a kiln the contained precious stones will be 
procured uninjured, and in sufficient numbers to make this mode of obtaining them a 
source of profit. 
I had some blasting done at Sagvin, which disclosed a few small off-coloured 
rubies, of no value, in the rock. The rubies obtained in the second hill in the conso¬ 
lidated red earth have hitherto been looked upon as being in the matrix, but this is 
not the case. 
The foregoing description of the manner in which these mines are worked by the 
natives tends to show how primitive were the modes adopted at the time of my visit 
in 1888. Tn the hands of Europeans, with capital at command, the quantity of 
precious stones produced should be greatly increased were proper methods of working 
adopted. The great drawback to Twinlone mining is the quantity of water in the 
ruby-bearing gravel, and it would be a costly matter to drain such valleys as Mogok, 
Kathay, Kyatpven, and Yeboo. But, could this be effected in the Mogok Valley 
there is a large quantity of ruby sand and gravel still remaining to be dealt with. 
In some places adits could be driven at the foot of the hills into the limestone, 
thereby tapping the deposits in its caves and natural channels, which, from experience 
gained by native miners, is known to be more or less rich in rubies. 
In February, 1888, the number of mines, consisting of Twinlones, Hmyaudwins, and 
Loodwins, was 77, employing 771 native miners. No quarry mines were then in 
operation, owing to the prohibition placed on the use of gunpowder by the Govern¬ 
ment. For the same reason, many of the Loodwins were lying idle. C. B. B. 
VI. Petrology. 
The large and interesting collections brought home by Mr. C. Barrington Brown, 
which have been submitted to me for study by the Secretary of State for India, 
consist of the following classes of materials :— 
(a) Specimens of the rocks of the district—gneisses, granulites, pegmatites, 
crystalline limestones, &c.—collected in situ. 
(b) Selections of rock-fragments and minerals found in the ruby-bearing gravels. 
The rock-fragments are for the most part similar to those collected in situ ; but they 
are often water-worn and are sometimes in a very disintegrated condition, owing to 
the action of atmospheric denudation. 
(c) Specimens of the reddish-brown earth in which the rubies and other gem- 
minerals occur. 
(cl) Samples of the materials obtained by the rough washing of the ruby-earths 
before picking. 
In dealing with these materials I have studied the rock-specimens, whether collected 
in situ or as derived fragments in the gravel, by the aid of thin sections under the 
