FART 3.] Mallet: On M^sorin and Atacamite/m>i the Nellore Bistrict. 167 
was very considerable, and tbat the working of the mines “ had not been given 
up for want of ore, but from the jealousy of the Rajahs, who wished to hide 
such a treasure as long as possible from their superiors.” Specimens of copper 
ore were obtained by Dr. Heyne, from near the surface, in several localities. 
Most of it was “malachite and mountain green,” but there was also a dark-colored 
ore, intimately associated with the above, a sample of which was sent to London, 
and analysed by Dr. Thomas Thomson. His results were published in the 
Philosophical Transactions for 1814, and were reprinted as an appendix to Dr. 
Heyne’s work above refeiTed to. Dr. Thomson described the ore as follows: 
“ All the specimens of this ore wMch I have seen are amorphous ; so that, as far 
as is known at present, it never occurs crystallized. Quartz crystals indeed are 
imbedded in it abundantly and very irregularly. Sometimes they are single, 
sometimes they constitute the lining of small cavities to be found in it. These 
crystals are all translucent. In some rare cases they are colorless ; but by far 
the greater number of them are tinged of a yellowish-red, and some few of them 
are green. The mineral is likewise interspersed with small specks of malachite ; 
and with dark, brownish-red, soft particles, which I found to consist of red oxide 
of iron. 
“The color varies in consequence of the irregular distribution of these 
extraneous substances. One specimen, which was the most free from the 
malachite and the red particles, was of a dark blackish-brown color. But in 
general the color is a mixture of green, red, and brown; sometimes one and 
sometimes another prevailing. Small green veins of malachite likewise traverse 
it in different directions. 
“ The fracture is small conchoidal, and in some parts of the mineral there 
is a tendency to a foliated fracture. The lustre is glimmering, owing, I conceive, 
to the minute quartz crystals scattered through it. The kind of lustre is resinous ; 
and on that account and the varieties of colors, this ore has a good deal of the 
aspect of serpentine. 
“ It is soft, being easily scratched by the knife. * It is sectile. The streak 
reddish-brown. The specific gravity 2-620. 
“It effervesces in acids and dissolves, letting fall a red powder. The 
solution is green or blue, according to the acid, indicating that it consists chiefly 
of copper.” 
The result of Dr. Thomson’s analysis was as follows 
Carbonic acid 
. 
. 16-70 
Peroxide of copx^er 
. 60-75 
Peroxide of iron 
. 
. 19-50 
Silica 
. 2-10 
Loss 
-95 
100-00 
The oxide of iron and silica he regarded as mechanically mixed, and he 
therefore considered the ore to be an anhydrous carbonate of copper, and a new 
* The hardness is given as 4°25 in T)r, Thomson’s Mineralogy of 183G. 
