PART 4.] 
8i<x.hr : Copper deposits of Singhbhhi. 
89 
Red copper ore, in solid masses from the size of a nut to several feet in diameter in a 
silicious matrix, sometimes filling the whole lode and enclosing angular pieces of quartz, 
sometimes in strings and flakes ramifying through the rock. This is the most important 
ore, seldom indeed pure, almost always mixed with blaok copper and iron oxide. As the 
malachite is due to the further decomposition of this ore, so is it of glance-eopper; some 
specimens show the three states. It is difficult to find red copper entirely free from copper- 
glance ; apparently pure red copper specimens have given 8 per cent, of sulphur. The mixture 
with iron oxide varies from 0 25 to 18 per cent. It is too always mixed with black copper; 
and it was interesting to know if the proportion were constant; analysis showed it to vary 
from 63'7 per cent, sub-oxide and 33’6 of oxide to 60T1per cent, of sub-oxide and 4674 
of the oxide. It is only an indefinite mixture. Often the oxyde is in excess, the ore being 
dark brown, with black metallic streak. The common variety is brown red to cochineal red, 
with red streak, and in pure pieces, a fine crystalline texture. This quality, with hardness 
of 3, sp. gr. 5'623, gave— 
Sub-oxide ... 
Black oxide 
Silica 
Alumina and iron 
Lime 
Magnesia ... 
Others gave traces of manganese and bismuth. 
Blade copper occurs only as a coating, and at most in strings as thick as the back of a 
knife and always mixed with red copper and iron oxide. 
Copper-glance, massive, mostly in kernels. It is at all events the original undecomposed 
ore; seldom pure, almost always with iron oxide. 
Copper pyrites seldom found; and only sprinkled here and there. 
Azurite, as a crust. It is remarkable how seldom it appears where malachite is so 
abundant; I only know of one locality. 
Libethenite and Chalcophyllite, in small crystals in the old refuse heaps; similarly 
Chrysocolla. 
Native copper, in massy rosettes and flakes; rare, and only where surface water can 
penetrate; associated with malachite, of which it seems to be a reduction and not of red 
copper. 
Copper urtmite was found on Lopso. 
Iron ores, —Brown iron ore; in the upper levels often filling the whole lode, as ochre 
or as solid brown haematite. 
Magnetic iron in crystalline granular masses, sometimes even filling the whole lode 
mostly mixed with specular iron (Eisenglanz). Analyses of fragments of the old copper 
reguliis gave traces of silver and gold, and 10 per cent, of iron. Assays made in London 
proved the ores to contain silver: an ore of 31 per cent, of copper gave 0'0678 per cent, of 
silver, one of 60 per cent, of copper gave 00039 of silver. The silver then cannot he prin¬ 
cipally contained in the copper ore, hut in the gangue. 
10. Distribution of the ore, —Copper is not the only metal this deposit contains ; iron 
predominates; so that one may describe the deposit as one of iron ora rich in copper. The 
copper-contents are themselves very variable, from traces up to the richest ore. Tire action of 
the intruded diorites appears to influence the proportion of copper; they may come quite to 
the surface or only produce a north-south upheaval, the richest copper deposits always being 
in their neighbourhood. In the preponderating quartzoso gangue the ores occur in loaves or 
threads, from paper thickness to several inches, ramifying through the mass; sometimes 
binding angular quartz fragments, sometimes in compact masses; often tilling the whole 
vein. Elsewhere they show in lenticular lumps from the size of a hazelnut to that'of the 
head, having flien generally a covering of talc or chlorite in the qnartzose base. Sometimes, 
but seldom, the qnartzose veinstone fails, and contorted, crushed, broken chlorite- and talc- 
schist enclose lumps of quartz and strings and pieces of ore. Once or twice the veinstone 
was quite porphyritie. 
63'72 
33-60 
1-02 
0-76 
0-64 
0-10 
99-83 
