288 SYSTEMATIC DESCRIPTION OF PRECIOUS STONES 



In the Kalu Ganga, between Ratnapura and Caltura, most of the gems are washed from 

 the sands above small rapids in the river. 



The gem mines of Ukkette Demy, near Ratnapura, were visited in 1889 by J. Walther, 

 of Jena, who was kind enough to furnish the following unpublished details : The mines lie 

 in a valley basin about & kilometres wide, in which several side streams deposit the 

 debris weathered from the surrounding ancient crystalline rocks, such as gneisses, &c. The 

 strata in which the mines are sunk include an upper layer of 80 centimetres of mud, then 

 50 centimetres of white sand, with a few bands of black vegetable matter ; beneath this a 

 metre of dark yellow clay, and then the gem layer consisting of a tough clay, which may be 

 white, yellow, red, or green, and encloses much-decomposed boulders of the surrounding 

 crystalline rocks. The gem-bearing clay, which rests on a bed of gravel 3 metres thick, 

 is richest when white and poorest when green. The precious stones have doubtless been 

 derived from the gneisses, &c., of the neighbourhood, since grains of sapphire have frequently 

 been found in decomposed boulders of these rocks contained in the deposit. 



The sapphires of Ceylon are not of very good quality ; though a few stones of a rich 

 colour are found, the majority are too pale to be of any great value. Star-sapphires are 

 not of unusual occurrence, and yellow (" oriental topaz ") and white (leuco-sapphii'e) stones 

 are abundant, while parti-coloured sapphires are not infrequently met with. The original 

 crystalline form of some stones is distinctly recognisable, although the edges are usually not 

 quite sharp ; others are much worn and rounded. Large stones are rarely found here, and 

 the ruby is far less abundant than the sapphire. 



Another important locality at which, since 1881 or 1882, sapphires in large numbers 

 have been found, is the Zanskar range of Kashmir, in the north-west Himalayas. The 

 exact locality of these finds was for a long time a secret, which was jealously guarded, 

 especially from Europeans, first by the original discoverers and then by the Government of 

 Kashmir. The first geologist who succeeded in visiting the locality was Mr. T. H. D. 

 LaTouche, of the Indian Geological Survey. 



According to his report these deposits are situated in a small upland valley in the upper 

 part of the district of Pddar, about thirteen days' journey south-east of Srinagar, the capital 

 of Kashmir, a few miles to the east of the village of Machel, and a little west-north-west of 

 the village of Soomjam. Soomjam is higher than any other village on the south-western 

 slopes of the lofty Zanskar range. It is about half a day's journey down from the Umasi 

 Pass, and has an altitude of 11,000 feet. It lies in latitude 33° 25' 30" N., and longitude 

 76° 28' 10" E., on the Bhutna river, a tributary of the Chindb. 



The valley in which the sapphires are found is 1000 yards long and 400 yards wide at 

 its lower end ; it has an elevation of 13,200 feet above sea-level, and its floor rises towards 

 the north-west, the average angle of slope being about 20°. The first find is said to have 

 been made in the sapphire-bearing rock which forms a precipice at the head of the valley. 

 This rock, which was laid bare by a landslip, is at an altitude of 14,800 feet, and lies very 

 near the limit of perpetual snow. A large number of gems were at first won from the solid 

 rock ; very soon, however, it was discovered that they existed in equal abundance in the 

 loose detrital material weathered from these rocks and deposited on the floor of the valley. 



The rocks of the district, mainly mica-schists and garnetiferous gneiss with interfoliated 

 crystalline limestone, are penetrated by veins of granite, and it is in these veins that the 

 sapphire, associated with an abundance of dark-brown tourmaline, is found. The material 

 formed by the weathering of the granite is laid down in the valley as a white bed of little 

 thickness, and is described as being overlain by a reddish-brown earth. The gems can be 

 picked out by hand from this deposit " like potatoes," though they are, of course, also won 



