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a mixture of almost imperceptible particles of
Sulphuret Qf silver, and black prismatic silver,
fizhlerz is accompanied with fglaserz, with
* See the very instructive work of M. Daubuisson, under the title of Description des Mines de Freiberg. I have followed in the course of this chapter, in whatever relates to the art of mining, and the mode of occurring of minerals, the terminology of M. M. Brochant, Daubuisson, and Brongniart; '
I . 154 POLITICAL ESSAY ON THE [soon 11..
variegated copper ore (bunt lrupfererz), sul. phuret of zinc and vitreous copper (kupfer. glas,) which is only wrought for the extraction of the silver, without applying the copper to any use. The graugiltigerz or antimoniated grey copper described by Mr. Karsten, is found at Tasco, and in the mine of Rayas, south east from Valenciana. The muriate of silver which is so seldom found in the veins of Europe, is very abundant in the mines of Catorce, Fresnillo, and the Cerro San Pedro, near the town of San Luis Potosi. That of Fresnillo is frequently of an olive green, which passes into leek-green. Superb specimens of this colour have been found in the mines of Vallorecas, which belong to the district de los Alamos in the intendancy of Sonora. In the veins of Catorce, the muriate of silver is accompanied with molybdate of lead, (gelb blei-erz) and phosphate of lead (grim bleierz.) From the last analysis of Mr. Klaproth, it appears that the muriate of silver of America ‘*, is a pure mixture of silver and muriatic acid, while that of Europe contains oxid of iron, alumine, and especially a little sulphuric
* The Mineralogists at present distinguish four kinds of muriate of silver, the common, the earthy, the conchoidal,
"-and the radiated. The two last species, which are exceed
ingly beautiful, have been described by Mr. Karsten: they -are among the minerals brought by me from Peru. Karsten, in the Magazine der Berliner Gesellschqft Naturforschender Jreunde, b.,i.§ 156. Klaproth’s Beilriige, b. iv.§ 10.
acid. The red silver ore constitutes a principal
In some parts of New Spain, the operations
minated in particles imperceptible to the naked eye. This ochreous mixture, which they call paco in Peru, and of which we have already had occasion to speak, is the object of ,considerable operations at the mines of Angangueo, in the intendancy of Valladolid, as well as at Yxtepexi, in the province of Oaxaca. The ores of Angangueo, known by the name of ecolorados, have a clayey appearance. Near the surface, the brown oxide of iron is mixed with native silver, with sulphuret of silver, A and black prismatic silver (spriidglaserz), all three in a state of decomposition. At great depths, the vein of Angangueo contains only galena and iron pyrites, yielding but a small quantity of silver. Hence the blackish pacos, of the mine of Aurora d’Yxtepexi, whieh must not be confounded with the negrillos of Peru, owe their richness rather to the glaserz, than -to the imperceptible filaments of native dendritic silver. The vein is very unequal in its produce, sometimes sterile, and sometimes abundant. The colorados of Catorce, particularly those of the mine of Conception, are of a tile-red color, and.mixed with muriate of silver. In general it is observed both in Mexico and Peru, that those oxidated masses of iron which xcontain silver, are peculiar to that part of the veins, nearest to the surface of the earth. The pacos
cnsv. xr-] KINGDOM OF NEW SPAIN. I57
of Peru present to the eyes of the geologist,