Everything we have discussed until this point has
been the exclusive merit of nature. Now let’s see
what happens with the passage to the expert hands of
man, when they transform a stone in a bead gem handcrafted
jewelry stone. Most gemmiferous deposits have been discovered
by chance, without the use of modern techniques or scientific
bases. Areas still exist today where the methods of mining
are the same as they were 2000 years ago! The simplest
method of mining is extraction of the gemmiferous gravel
from the dry beds of ancient waterways. This procedure
involves digging a small vertical pit in the gravel and,
if conditions permit, in the subsequent horizontal drifts
starting from the base of the pit. The crystals, which
grow on the interior of a mother rock, are broken free
using hand tools, compressed air or simple explosives.
The disintegrated rocks are then washed, and the gemmiferous
material, which is heavier than rock, is deposited at
the bottom of the pans. Mining from secondary deposits
is different but likewise simple. The entire mine cover
is removed, which gives this type of mining its name
open mine. In this case as well, jets of water are used
to break up the subsoil if necessary. From this point
forward, all procedures are similar to those previously
discussed. Once the gems have been mined, they just have
to be classified!
|
