^6 Dr, Thomson's Analysis of 
crystallized. Quartz crystals indeed are imbedded in it abun- 
dantly 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 colourless; 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, par- 
ticles, which I found to consist of red oxide of iron. 
The colour varies in consequence of the irregular distribu- 
tion of these extraneous substances. One specimen, which 
was the most free from the malachite and the red particles, was 
of a dark blackish brown colour. But in general the colour 
is a mixture of green, red, and brown; sometimes one, and 
sometimes another prevailing. Small green veins of mala- 
chite 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 variety of colours, 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 pow- 
der. The solution is green, or blue, according to the acid, 
indicating that it consists chiefly of copper. 
After a few preliminary trials to ascertain the nature of the 
constituents of this ore, I adopted the following mode of 
analysis. 
