Diamonds have been a source of fascination for centuries. They are the hardest, the most imperishable, and the brilliant of all precious stones. The word "diamond" comes from the Greek word adamas, meaning "unconquerable".
A diamond is a transparent gem made of carbon, one of the earth's most common elements. The formation of diamonds began very early in the earth's history, when the condensation of solid matter into a sphere caused the centre of the planet to become subjected to incredible extremes of temperatures and pressure.
It was these conditions that caused deposits of carbon to begin to crystallise deep in the earth. As the earth's surface cooled, volcanic activity forced streams of magna (liquid rock) to the surface, carrying with it the diamond crystals. Later, the diamond-bearing rock hardened, encasing the diamonds in vertical volcanic "pipes".
But not all diamonds are found where they first came to the surface. Subsequent erosion of the topsoils over millions of years washed some of the diamonds into streams and rivers, and sometimes as far away as the sea. It is highly probable that they were first discovered in areas such as these, far away from their original location.
The atomic structure of a diamond gives it the property of being the hardest substance known to man, natural or synthetic. The diamond is thousands of times harder than corundum, the next hardest substance from which rubies and sapphires are formed. Even after many years of constant wear, diamonds will preserve their sharp edges and corners when most other stones will have become worn and chipped.
However, many people expect a diamond to be unbreakable. This is not true. A diamond's crystal structure has "hard" and "soft" directions. A blow of sufficient force, in a very exact direction, can crack, chip, split or even shatter a diamond.