OCCURRENCE OF PRECIOUS STONES IN N.S.W. 233 
in a Pleistocene drift on the Severn River, and was sold to the 
trade for £10. I examined a parcel of nine pounds in rough of 
sapphire, collected in and around Emmaville, without finding one 
faultless gem of half acarat. Most of the stones were dark blue, 
many almost black, but all showed prismatic or pyramidal faces 
and bright basal cleavage surfaces. The more transparent stones 
showed a dark blue-green when viewed across the prism, and 
a deep blue when seen along the axes. Quite a number were 
banded in alternate blue and colourless lines parallel to the basal 
plane. 
Plate 16, fig. 2, shows the general appearance of the New 
England sapphires. The peculiar surface pitting shows well on 
the original photograph, but is rendered somewhat indistinctly in 
the process block. This character is not seen in the sapphires 
from the southern districts, nor is it noticeable on any Queensland 
Sapphire that I have seen. 
On the extreme right of Plate 16, fig. 2, a few crystals can be 
found showing parallel lines running obliquely across the prisms. 
In one Specimen the alternate lines have a reddish tinge which 
gives the crystal a remarkable appearance. It is most unusual to 
find any Suggestion of a cleavage in sapphire other than the basal. 
The lines referred to are certainly structural. 
Professor Judd and Mr. Barrington Brown have recently 
described some structures ina “ Contribution ta the History of 
Corundum.”! The paper deals with rubies of Burma. The 
authors speak of the corrosion of rubies in deep seated rock masses. 
he corrosion follows “certain planes of chemical weakness, 
analogous to the cleavage planes, gliding planes, and other direc- 
tions of physical weakness. The principal of these solution 
Planes is the basal plane. Other less pronounced planes of 
chemical weakness exist parallel to the prism faces. Unaltered 
corundum is like quartz, destitute of true cleavage, and breaks 
with a perfectly conchoidal fracture. If, however, gliding planes 
2g es ee 
1 Proceedings of the Royal Society of London, No. 345, p. 392. 
