Why Does a Diamond Sparkle?

Suppose diamonds were not as rare as they are. Suppose they didn't cost much and almost everyone could have them. Would dia­monds still be valuable?

Two things would probably make people still want to have dia­monds. One is that a diamond is the hardest substance known to man, so diamonds would still be very useful in industry. The second is that diamonds would still be beautiful, and so people would still enjoy looking at them.

Diamonds are the result of a process that took place in nature. Millions of years ago, the earth was gradually becoming cooler. At that time, there existed beneath the ground a mass of hot liquid rock. This mass was subjected to extreme heat and pressure. As a result of this, molecules of carbon became packed together in dense, clear crystals. A diamond is simply a crystal of pure carbon.

When a diamond is found in "rough" form, its outside appearance is rather dull. Now man takes over to make it into the sparkling gem we all know about. Most diamonds are sawed in two, and each half is shaped and cut into a round diamond called a brilliant.

Then little faces, or facets, are cut into the diamond. The aver­age brilliant is cut into fifty-eight facets, or even more. These facets make a diamond sparkle.

The reason for this is that a diamond has a very high refractive power. This means that when light enters it, the diamond bends the light more than other substances do. The light, instead of passing through the diamond, is bent so that it is reflected back into the stone. So a greater amount of light is returned to our eyes when we look at a diamond and it looks more brilliant. The diamond also breaks up the light into its different colours, which gives a diamond its "fire".

Did you know that diamonds were not worn as personal orna­ments until 1430, when a Frenchwoman called Agnes Sorel started the custom? From then on the custom spread.