40 THE PROSPECTOR'S HANDBOOK. 



and silver (usually the former). Perhaps ho keeps a look- 

 out for lead and copper ores, but very seldom (even when in 

 a granite country) thinks about searching the streams for 

 tinstone or the hills for tin-bearing lodes. He may pass by, 

 or even handle and throw aside, such unmetallic-like minerals 

 as some of the silicates, carbonates, chlorides, &c., simply 

 because of their lightness of weight, or because they do not 

 come up to his notions about what a metal-bearing rock 

 should be. He may even discard some of the heavy mine- 

 rals on account of their nature being disguised by the pre- 

 sence of iron oxide, which may give them the appearance of 

 an iron ore. Hence the desirability of examining carefully 

 all sorts of minerals and submitting them to tests. 



Although in this chapter many of the different metallic 

 compounds are described, it would be well if the prospector 

 made himself especially well acquainted with the appearance 

 of the various oxides, and in a lesser degree with the car- 

 bonates, chlorides, &c. The sulphides which are found deep 

 down a lode become chiefly converted to oxides on the sur- 

 face. Take, for instance, a lode in which copper pyrites 

 and iron pyrites exist several fathoms down. On the out- 

 crop there would probably be the rusty colour due to iron 

 oxide ; and black oxide (perhaps the red) of copper, and 

 also the green or bluish stain of carbonate of copper might 

 be distinctly noticed. Still, whether the prospector comes 

 across oxides, carbonates, chlorides, sulphides, or metal in 

 the native state, recourse to the following pages may, per- 

 chance, help him to solve the question as to what the true 

 nature of the particular mineral is. 



ALUMINIUM. 



This metal is not found in the native state, but in combi- 

 nation with silica, oxygen, fluorine, &c. 



Corundum, sapphire, and ruby are nearly pure alumina 

 (oxide of aluminium). Emery is a more impure variety. 

 The silicate is very abundant and is a constituent of the 

 older rocks, of all clays, &c. The presence of alumina is 

 known by heating the substance in the B.F., then moisten- 

 ing it with nitrate of cobalt solution and again heating. A 

 blue, lustreless colour will indicate the presence of alumina, 



