Since
which the price of fine carbon rose rapidly to $95 two or three years
ago, dropping back to the present price of $85 per carat. Stones down
to one carat in weight are occasionally used in mining drills for some
purposes. The smaller ones are used for emery-wheel dressers, turning
hard stones and hard rubber, drilling semi-precious stones,
eyeglasses, etc.
In
1904-6 there was an enormous consumption of carbon in the United
States, owing to the great development of the machine industry. Sales
amounted to nearly $3,000,000 annually; considerably more than the
amount declared in the exports of Brazil. Prime carbon brought as high
as $95 per carat. At present the price at the fields is about £10 to
£10. 10s. per carat.
Among
other things, diamonds are used for points, lens, drills, dental
drills, pivot jewels, glaziers' tools, glass cutters' sparks, etc. Bort
is used for stone saws, prospecting drills, emery-wheel dressers, wire
dies, electrical jewels, small tools and to crush for powder.
Misunderstanding
regarding prices arises from a habit of quoting prices in trade
journals without stating where those prices rule. The price of
carbonado in the Transvaal has been quoted at $60 when it was selling
for much less in New York, and there are great differences between
prices at the mines and in the various
