Gem-Stones and Their Distinctive CharactersSmith, George Frederick Herbert
Science
Gem-Stones and Their Distinctive Characters
Smith, George Frederick Herbert
Precious stones
The old method, which is still in use, for roughly fashioning diamonds
is that known as bruting, from the French word, _brutage_, for the
process, or as shaping. Two stones of about the same size are selected,
and are firmly attached by means of a hard cement to the ends of
two holders, which are held one in each hand, and rubbed hard, one
against the other, until surfaces of the requisite size are developed
on each stone. During the process the stones are held over a small
box, which catches the precious powder. A fine sieve at the bottom
of the box allows the powder to fall through into a tray underneath,
but holds back anything larger. By means of two vertical pins placed
one on each side of the box the holders are retained more easily in
the desired position, and the work is thrown mainly on the thumbs.
This work continued day after day has a very disfiguring effect upon
the hands despite the thick gloves that are worn to protect them; the
skin of the thumbs grows hard and horny, and the first and second
fingers become swollen and distorted. When the surfaces have thus been
formed, the stone is handed to the polisher, who works them into the
correct shape and afterwards polishes them, the stone passing backwards
and forwards several times between the cutter and the polisher. The
table, four templets, culet and four pavilions are first formed and
polished, so that the table has a square shape. Next the quoins are
developed and polished, and finally the small facets are polished on,
not being shaped first. In modern practice the process of bruting has
been modified in some cases by the introduction of machinery, and the
facets are ground on, with considerable improvement in the regularity
of their size and disposition, and reduction in the amount of polishing
required. Moreover, to obviate the loss of material resulting from
continued grinding, large stones are first sliced by means of
rapidly-revolving copper wheels charged with diamond powder.
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Elsewhere in the archive
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account