onsistence, and colour. Some are white and grey,
mixed with red or bluish spots, called _plata blanca_ or white silver;
of which sort the one in the Lipes mines mostly consists. For the most
part, some little grains of silver are to be discerned, and very often
small branches are seen, ramifying along the layers of the stone. Some
ores are as black as the dross of iron, and in which no silver is to
be seen, which is called _negrillo_ or blackish ore. Sometimes the ore
is rendered black by admixture of lead, and is called _plombo ronco_,
or coarse lead, in which the silver appears as if scratched by
something harsh. This ore is generally the richest in silver, and from
it also the silver is got at the smallest charge; as instead of having
to be moulded or kneaded with quicksilver, it has only to be melted
in furnaces, where the lead evaporates by the force of fire, and the
silver remains pure behind. From this sort. of mines, the Indians drew
their silver before the coming of the Spaniards, having no knowledge
of the use of mercury, and they accordingly only wrought those mines
of which the ore would melt; and, having but little wood, they heated
their furnaces with _ylo_, the dung of the _Llamas_ or Peruvian sheep,
placing their furnaces on the sides of mountains, that the wind might
render their fires fierce.

There is another sort of black ore, in which the silver does not at
all appear; and which, when wetted and rubbed against iron, becomes
red. This ore is called _rosicler_, signifying that ruddiness which
appears at the dawn of day. This is very rich, and affords the finest
silver. Another kind, called _zoroche_, glitters like talc, and is
generally very poor, yielding little silver: Its outer coat is very
soft and of a yellowish red, but seldom rich; and the mines of this
sort are wrought on account of the easiness of extracting the ore,
being very easily dug. Another kind, not much harder than the last, is
of a green colour, called _cobrissa_ or copperish, and is very rare.
Although the silver usually appears in this kind, and it is almost
mouldering, it is the most difficult of all to manage, as it parts
very difficultly with the silver. Sometimes, after being stamped or
reduced to powder, it has to be burnt in the fire, and several other
expedients must be used to separate the silver, doubtless because
mixed with copper. There is another very rare sort of ore, which has
only been found in the mine of _Cotamiso