ECONOMIC GEOLOGY. 



373 



in 1905, when 161 lbs. of rubellite, valued at £1,501, wera obtained. 

 In 1907, however, the output fell to 20 lbs., valued at £293, and 

 in 1909 only seven stones are reported to have been found, worth 

 £26. The gems are sold to the Chinese, by whom they are in great 

 demand. 



The tourmaline mines of Maingnin, described by Mr. E. C. S. 

 ,„ . George in the Records in 1907, 1 are situated 



Maingnin. , _. . . . , 



m the btate ot Mongmit (Momeit), to the 

 north of the Ruby Mines District. The gems are said to be 

 obtained from a decomposed granite. The mines appear to be 

 worked in a desultory manner, and the outjmt is small, only 5 lbs., 

 valued at £36, having been obtained in 1908, the last year for which 

 returns have been received. 



Gold. 



The streams that drain the areas occupied by the slates and 

 quartzites, with their associated quartz veins, 



Mode of occurrence. \ , . . „ 



ot the (. haung-Magyi series, usually carry a 



certain amount of gold in fine particles, and I have seldom tested 

 one of them without finding at least a 'colour.' Gold washing 

 is practised by the natives in a desultory fashion in many places, 

 when they are not employed in tilling their fields, and the fre- 

 quency with which gold occurs is denoted by the prevalence of its 

 Shan appellation ' hkam ' in their place-names (Loi-hkam, ' gold- 

 mountain,' Nam-hkam, 'golden stream,' etc.). In the year 1906 an 



attempt was made to exploit one of these 

 tu2 amma llmlSi " S VCn " alluvial deposits in the Namma (not the 



stream from which the coal-field derives its 

 name, but a tributary of the Salween flowing by Man Namluk (J 1), 

 due east of Lashio), by means of a steam dredger, brought to the 

 spot and put together at the cost of great labour and expense. 

 Previous prospecting operations had shown that an average return 

 of 15 grains of gold to the cubic yard might be looked for, but 

 it was found that the gravel, having been consclidateel in places by the 

 infiltration of calcareous tufa was not amenable to the method em- 

 ployed, and after a short trial the enterprise proved abortive/ 



1 /bid, Vol. XXXVI, PI. 3, |). 233, 

 t, 1 General Report; /bid, Vol. XXX VII, Pt. I, p. 31, 



