OCCURRENCE OF PRECIOUS STONES IN N.S.W. 243 
of 2-67, while a beryl from Ophir, tested by Professor 
Liversidge had a specific gravity of 2°708.! 
(e) Chemical Composition.—The following is the composition of 
an emerald from Emmaville as determined in my laboratory 
about two years ago by Mr. James Petrie. The analysis 
of a crystal from Paavo is also given for comparison. This 
latter is taken from Dana’s ‘Descriptive Mineralogy,’ sixth 
edition, p. 407. 
Emmaville, N.S. Wales. Paavo. 
H,O (on ignition)... 0°62 
SiO, ee ee ee i 
Al,O, wii is 4a ie 19-26 
BeO... e i eae ice 14:01 
CaO... seu we 2 Te 
‘MgO res rat! | 
Na,O a ne OO4 
100-00 99-64 
Specific gravity 2°73. 
BrErYLs. 
Beryls, as a matter of course, occur with the emerald. The 
more correct statement of the relation between emerald and beryl 
is that around Emmaville beryl? is common, and that in a few 
localities there is a small proportion of the emerald. Plate 15 
Shows a number of beryls of the natural size, all from New 
England. The longest gem on the plate was found by a Mr. 
Stanley at Stanburra, when ground-sluicing a patch of decomposed 
‘separa er 
* Minerals of New South Wales by Prof. Liversidge, p. 199. 
ie have cut several crystals of beryl into microscopic slices. These 
Sections when parallel to the basal plane show successive hexagons from 
the centre outward, the lines being formed of liquid or gas cavities. The 
cavities are drawn out parallel to the faces of the prism. When slices 
Parallel to the vertical axis are examined the cavities are also seen to be 
drawn ont in the direction of the vertical axis, so it is evident that the 
Successive shells as they were formed compressed the layers below them 
im all directions around the vertical axis. 
