As regards other kinds of metal, although some rich ores are found,
still, unless the veins contain a large quantity of ore, it is very rarely worth
while to dig them. The Indians and some other races do search for gems in
veins hidden deep in the earth, but more often they are noticed from their
clearness, or rather their brilliancy, when metals are mined. When they
outcrop, we follow veins of marble by mining in the same way as is
done with rock or building-stones when we come upon them. But
gems, properly so called, though they sometimes have veins of their own,
are still for the most part found in mines and rock quarries, as the
lodestone in iron mines, the emery in silver mines, the lapís judaícus,
trochítes, and the like in stone quarries where the diggers, at the bidding
of the owners, usually collect them from the seams in the rocks.10 Nor does the
miner neglect the digging of “extraordinary earths,”11 whether they are found
still, unless the veins contain a large quantity of ore, it is very rarely worth
while to dig them. The Indians and some other races do search for gems in
veins hidden deep in the earth, but more often they are noticed from their
clearness, or rather their brilliancy, when metals are mined. When they
outcrop, we follow veins of marble by mining in the same way as is
done with rock or building-stones when we come upon them. But
gems, properly so called, though they sometimes have veins of their own,
are still for the most part found in mines and rock quarries, as the
lodestone in iron mines, the emery in silver mines, the lapís judaícus,
trochítes, and the like in stone quarries where the diggers, at the bidding
of the owners, usually collect them from the seams in the rocks.10 Nor does the
miner neglect the digging of “extraordinary earths,”11 whether they are found