Mohave County miner., 1884-03-30
Underground Treasures.
How the Minerals Exist and How Their Character May
 Be Determined.

the surface, showing the presence ol verdigris, which IS produced through chemical action. The varlous spe cies of copper ores are most abun dant near trapdykes. The pyrites are generally found in lead mines, and in granite and clay slate. Cop per very rarely occurs in new forma- tions as along the Atlantic and gulf borders, add the Mississippi Valley, south of Cairo.
 Lead is seldom discovered in the surface soil. It is also Tn va1n to look for 1t in the coal regions or along the coast. It must be sought in steep hills, in limestone or steep rocks. A surface cut by frequen nt ravines, or covered by vegetation in lines, indicates mineral cre7ices. The galena from the slate is said to con tain more silver than that from the limestone. The purest specimens of galena are the poorest in silver; the small veins are richest Tn the more precious metal. A lead vein is thick est in limestone, thinner in sand stone and thinnest in slate.
 Silver is usually found with lead ore and copper. States and sand stones intersected with igneous rocks, as trap and porphyry, are good To- calities. Pure silver is oftener found in or mar iron ores and the dark brown zinc blende. The New Mex leo silver lodes are porous at the sur face, and colored, more or less, red or green. Any rock suspected of containing silver should be powder ed and dissolved in nitric acid. Pour off the liquid and add to It solution of salt. If white powder falls to the bottom, which upon exposure turns black, there is silver nit. Sil- yer mines increase Tn value as in depth, whereas gold dimin1shes as We descend.
 Gold deposits have their best To- calities amid the slopes of the Rocky and Alleghany mountains. Gold need not be looked for in the anthra cite and bituminous coal fields nor m limestone rocks. It is seldom found in beds of rivers. The thing itself is the surest indication of its existence. If soil or sand is washed and the particles of gold are not heavy enough to remain at the bot tom. but float away, the bed will not pay.
 The best prospects are among the streams rather higher up among the mountains and in the gravelly drift covering the slope of the valley be- low. Where the stream meets an obstacle in its path, or makes a bend, or has deep holes, there we may look for pockets" of gold. Black or red sands are usually richest. Gold bearing rock is slate or granite abounding in rusty looking quartz veins, the latter containing iron py- rites or cavities. Almost all iron pyrites and silver ores may be work ed for gold. When the quartz veins are thin and numerous rather than massive, and lie near the surface they are considered most profitable Few veins can be worked with profit very far down, As traces of gold may be found everywhere, no one should indulge in speculation before calculating the percentage and the cost of extraction. Gold hunting after all, is a lottery, with more blanks than prizes.
 The substances most freque ntly taken for gok. are ron pyrites, cop par pyrites a d mica. The p esioui metal is easily distinguished from these by its malleability, fattenlns under the hammer, and its great weight, sinking rapidly in water Any heavy mineral of a black, brown red or yellow color may be suspected of being iron. To prove 1t dissolv' some in oil of vitrol and pour an in fusion of nutgal or oak bark in, if l turns black iron Is present. If tol of rich magnetic ore costs more thai S4 at the furnace, good hematit
 more than s, and poor ores more
 than $I.5O or $2, they are too e1pen
 slve to pay, unless iron is unusual!
 high. Deep mining for iron is no
 profitable. Generally speaking,
 bed of good iron ore foot thick, wi
 repay the cost of stripping it of soi
 etc., twelve feet thick. Red and vel
 low earths, called ochres, contai : 1ron. Magnetic ore IS easily foun'
 by a compass.-Rocky Mountai
 Mining Review.