A Brief History
Diamond is the hardest
natural substance on earth, but if placed in an oven at 1405 degrees
Fahrenheit (763 degrees Celsius), it will vanish.
Only a small amount of carbon dioxide will have been released.
Diamonds are formed over a period of a billion or more years deep within the earth's
crust - about 90 miles (150km) below the surface - and are pushed to the
surface by volcanoes. Most diamonds are found in volcanic rock, called
Kimberlite, or in the sea, having been carried away by rivers after they were pushed to the surface. A diamond is 58 times harder than the
next hardest mineral on earth, corundum, from which rubies and sapphires
It was only during the 15th century when it was discovered
that the only way to cut diamonds was with other diamonds. Still, diamonds
are brittle; if hit hard with a hammer, they will shatter.
Not all diamonds are white. Impurities lend diamonds a hue of blue, red,
orange, yellow, green and even black. A green diamond is the rarest. Diamond,
however, is not the rarest gemstone. That title goes to a pure red ruby.
Diamonds actually are found in fair abundance; thousands are mined every
year. 80% of them are not suitable for jewelry and are used in industry.
The remainder, of higher clarity, are cut for the jewelry trade and end
up in jewelry stores.