PARTS,] Mallet; On M^sorin mid Atacamilefmn. the Nellore Bistricl. 169 
and while arranging the copper ores in the economic collection some time ago, 
I was struck with the outward resemblance of part of the Nellore ore to the 
Mysorin as described by Dr. Thomson. It is, however, only recently that I 
have had the ojiportunity of making a complete examination of it. 
The ore, as sent, occurs in irregular broken pieces of various sizes up to 
about three inches diameter. It is a most heterogeneous mixtui'e, made up of 
over half a dozen different minerals, some of which ai’e, however, much 
more abundant than others. Taken roughly in the order of their relative 
abundance, there arc visible to the naked eye, or with a lens;— 
Tbo (lark recldisli-brown ore in (luostion. 
Malacliite. 
Clirysocolla. 
Quartz. 
Yellowisli-browu ocliro, 
Chalcoclte. 
Calcite, 
Boruite.' 
Pieces of pure malachite are not to be found, the mineral being greatly 
mixed up with chrysocolla and other minerals. Some portions of it, owing to 
dissemminated reddish-brown specks, and specks of chaloocite, have a dark tinge. 
The chrysocolla, which is green and greonish-bluo in colour, occurs both mixed 
with the malachite, (fcc., and in the form of thin seams, and as the linings of 
small cavities. The quartz is crystalline and generally colorless or nearly so, 
but it appears to have a green or yellowish colour from being imbedded in mala¬ 
chite or chrysocolla or ochre, or from having such running through it in thin 
seams. The propoidion of chalcocite is quite small, but occasionally a tolerably 
pure mass an eighth of an inch long, or more, may be observed, and it can be 
seen scattered throirgh many pieces of the ore with the aid of a lens. Calcito 
is a rare mineral only observed on a few specimens in the form of very thin 
seams. Bornite is extremely uncommon: only a very few specks have been 
detected. Some pieces of the ore consist mainly of malachite and chrysocolla, 
others mainl}" of the dark-coloured ore. 
The most homogeneous portions of the latter have to the naked eye a dark 
reddish-brown colour, but viewed with a lens they are seen to be finely mottled 
in dark brownish-red and green. A thin section, which to the naked eye has a 
reddish-brown colour by reflected light, when viewed with a lens by transmitted 
light, shows this mottled structure still more plainly. The relative proportion of 
the two colours varies greatly. Occasionally a patch is found in which the green 
is almost absent. It is but rarely that one finds a surface of a quarter of an inch 
square that is not intersected by thin green seams of malachite and chrysocolla, 
which traverse the ore in different directions. Specks of chaloocite are also 
visible, and, very occasionally, those of bornite. The ore contains a few small 
cavities, pai’tially filled with red ochreous oxide of iron. 
1 Besides tlieae there arc visiljle in a few apccimons, which include some of the gangue-stone, 
hornblende, garnet, mica, &c., the matrix of the ore being, according to Lieutenant Newbold, inica- 
aud horiihleiide-schist. 
