234 J. MILNE CURRAN, 
and lamellar twinning be developed in corundum (like those so 
easily produced in the same way in calcite), parallel to the funda- 
mental rhombohedron of the crystals, then these gliding planes 
become solution planes.” The explanation applies exactly to 
the New South Wales stones. I had a face ground parallel to the 
basal plane on a large crystal marked in the manner described, 
and fine lines could easily be noted crossing the prism to join 
the parallel and inclined lines seen on the prism. 
Crystals are rather common that show 
a clear white line along the axes, and alter- 
nate layers of dark blue and light material 
are repeated from the centre outwards. 
Many of the stones are a light yellow 
colour, with the top of the prism just 
showing a spot of blue. A stone of this 
description was cut by Murfin, and made 
Cleavage fragment of 
a sapphire from Emma- 
ville district, showing a rather handsome gem. When putting 
alternating home of a final polish on the table a hexagonal 
cunt amaties barrell-shaped piece dropped out, leaving @ 
regular faced cavity for the full depth of the stone. I have a 
stone showing alternate bands of opaque blue and opaque white 
in successive hexagons from the centre. Small stones banded 
blue and honey-yellow, and blue and white, are not rare. 
As already stated, the sapphires from Tumberumba are all 
blue or blue-green. The New England stones are opaque blue, 
Antwerp blue, greenish-blue, greenish, bottle-green, and yellowish- 
green. 
Compared with good gems the New England stones show @ 
want of life, probably owing to being invariably too dark when 
they show the true rich velvet blue. I tried the experiment of 
having the dark stones shallow table cut. The effect was a want 
of life that the improved colour did not compensate for. There 
is one quality in the New England gems that is unsurpassed, and 
that is in their surface lustre, being exceeding bright, reminding 
one of the adamantine flash of sphene. 
