1895.] The Rubies of Burma and Associated Minerals. 389 



stone hills, 15 miles N". of Sagyin, have yielded rubies; while old 

 ruby workings were found in making the railway at Kauksay, 30 

 miles S. of Mandalay. It is also probable that ruby-bearing lime- 

 stones, and the alluvial earths derived from them, may be found in 

 portions of the adjoining Shan States. Indeed, at a point about 25 

 miles southward from Mogok, in the Shan State of Mainglon, Dr. F. 

 Noetling, of the Geological Survey of India, has found that rubies 

 have been obtained from the alluvium of a stream that flows from the 

 mountains that lie considerably to the S.E. of the Mogok District. 



The rubellite (red tourmaline) of the same district was found by 

 Mr. Barrington Brown not to occur in association with the rubies, 

 but to come from certain gneisses and schistose rocks. The locality 

 which yields this gem, so highly prized by the Chinese, is Nyoun- 

 gouk, 10 miles S.E. of Mogok ; the alluvium which yields the rubel- 

 lite appears never to contain rubies and spinels. Black tourmaline 

 (schorl) has been extensively worked, as shown by Dr. F. Noetling, 

 in the Shan State of Mainglon, not far from the rubellite locality. 



In the mountainous tract which includes the ruby districts, the 

 general trend of the hill ranges is from east to west. The bottom of 

 the Mogok Valley, in which the principal workings are situated, lies 

 at a height of 4,100 ft. above the sea; while the loftiest mountains of 

 the range to the north and east are the Chenedoung Peak, 7,362 ft., 

 and the Taungnee Peak 7,775 ft. above the sea-level. The alluvia of 

 the valleys of Mogok, Kathay and Kyatpyen are formed by streams 

 flowing southwards from this mountain chain ; while those of the 

 valleys of Injouk and Kabein are deposited by streams flowing in the 

 opposite direction. The district, which is a somewhat malarious one, 

 has an annual rainfall of about 80 inches ; but in March, April, and 

 May, the supply of water for mining operations is deficient. 



The mountains are composed of various gneissic and granulitic 

 rocks, occasionally passing into schists. Subordinate to the general 

 mass of gneisses, often containing garnets, are certain peculiar 

 varieties of foliated and massive rocks, including both acid and basic 

 types, with limestone bands, often of a highly crystalline character. 

 It was in these limestones that the rubies and spinels were found to 

 be embedded, associated with graphite, phlogopite, pyrrhotite, and 

 many other minerals. The sides of the hills are found to be shrouded 

 in a deposit of hill-wash, often 50 ft. in thickness, composed of 

 fragments, derived from the mountains, embedded in a clayey matrix. 

 On the bottoms of the larger valleys there are extensive level 

 deposits of alluvial matter, consisting of brown, sandy clay, resting 

 on coarse gravels, which in turn cover other argillaceous beds. It is 

 in these lower clay beds of the river alluvia, and in similar deposits 

 formed in gullies in the hill- wash, that the rubies, spinels, and other 

 gems of the district are found. 



