second
water, 25 per cent, of the third, while the remaining 65 per cent. is
called bort, a substance which, when crushed to powder, is of use in
the arts for cutting hard substances and engraving. This must not be
confounded with the carbon (carbonado) found in Brazil, an
uncrystal-line form of the diamond, which, from its structure, is
adapted for use iu drills for boring and tunneling rocks, etc., and has
never yet been found in South Africa. It is worth from six to ten times
as much as bort.
More
diamonds weighing over 75 carats after cutting have been found since
the African mines were opened than were known before. The Victoria, the
Great White, or the Imperial Diamond, is supposed to be from South
Africa. Concerning its early history very little is known; in fact,
where the stone was found is only a matter of conjecture—a remarkable
circumstance when we consider that it is the largest brilliant in the
world. The original weight of the stone was 457-1/2 carats, or 3-1/60
troy ounces; after cutting, 180 carats, valued at £100,000.
On
March 28, 1888, there was found in the De Beers mine an octahedral
crystal of diamond weighing 428£ carats; it is not entirely white,
having a slight yellow tinge. It was valued at £3,000. From its form it
is believed that it will cut into a brilliant of 200 carats, hence it
will be the largest known.
Production
of diamonds at the Griqualand West mines, Kimberley, De Beer's,
Duioitspan, Bultfontein, and St. Augustine, from September 1,1882, to December 31, 1887.
