GEM DISTRICTS OF CEYLON AND BURMA—ADAMS 317 
later times the yield has fallen off and is naturally subject to fluctua- 
tion from year to year according to the value of the stones recovered. 
This is indicated by the following figures, which show the value of 
the rubies produced in Burma in some recent years: 
fein ts ee eee ree ene een NE 1) $098) Bit 
AGTUEIA I AT BANGOD Seddon .fi9om sia 198, 603 
goodie! | Pivael pc onde pre ole bein co 165, 000 
ie 2S Os a eA Oe peer ee 212, 210 
TILE eB 2 ON eee rer 2 ST) a a 425, 800 
TCT OUR, aria cat sk. ea ce ae tl 224, 414 
ICT ea RPE ca OTS Cock 5), Raa eee 224, 409 
The great increase in the value of the output for 1919 was due 
in part to the finding in that year of an exceptionally valuable ruby, 
which was sold for three lakhs of rupees ($100,000). 
In addition to these gems, most of the jade, which is cut and 
polished in China, comes from northern Burma, and not very far 
from the jade mines are deposits of beautiful amber. As this country 
is opened up in future years other valuable deposits will probably 
also be found. 
A number of minerals of exceptional interest were obtained by the 
author in Burma, more especially from the district of the ruby 
mines about Mogok. Among these brief reference may be made to 
the following, a full description of which will be found elsewhere.® 
Chrysoberyl—This species has not hitherto been described from 
Burma, but was found near Mogok in the very unusual form of 
simple crystals, transparent and of a sea-green color, as well as in 
trillings of a pale yellow color. These show a number of forms which 
have never been observed in this species from other localities, 
Sillimanite-—This species occurs, although rarely, as rolled peb- 
bles accompanying the ruby in alluvial deposits. One specimen 
showed a cleavage apparently parallel to a macro-dome, which ren- 
ders it possible to measure the relative length of the vertical axis, 
which has been unknown in the case of this species hitherto. These 
measurements show that there is a close correspondence between the 
axial relations of sillimanite and those of the related minerals, 
andalusite and cyanite. 
Nepheline—This species, hitherto unknown from Burma, was 
found in a coarsely crystalline urtite associated with the crystalline 
limestones near Sinkwa. 
Sodalite—This mineral, having a deep lilac color, was found asso- 
ciated with nepheline at a second locality, namely, the Tajonngnadine 
mine at Mogok. 
6Frank D. Adams and R. P. D. Graham, “On some minerals from the ruby mining 
district of Mogok, Upper Burma.” Trans. Royal Society of Canada, Vol, XX, sec. 4, 1926. 
20837—2T. 22 
