Here are some diamond fun facts from The Encyclopedia of Trivia
Diamonds were first discovered in the riverbeds of the Golconda region of India over 4,000 years ago.
During the Middle Ages, only men wore diamonds, as a symbol of their courage and virility. Anne of Burgundy was the first woman to receive a diamond engagement ring. It was given to her by Maximilian I of Germany in 1477.
Scientists only realized that diamonds are the crystallized form of carbon in 1772 when Antoine Lavoisier made the discovery.
The South-African based De Beers Consolidated Mines launched a campaign in 1939 to promote further the tradition of diamond engagement rings. The N.W. Ayer agency of Chicago came with the line "A diamond is forever".
It rains diamonds on Saturn and Jupiter.
The diamond is the only gemstone composed of just one chemical element, carbon. Although crystal-clear, it is black when reduced to dust.