Diamonds have been valued for centuries for their brilliance, colorlessness, durability, and above all, scarcity. Three tons of ore must be mined to produce a one-carat diamond. This, combined with the fact that diamonds are unique in their ability to reflect all spectra of light equally, has made them the most valuable of rare gems. Furthermore, no one diamond is like any other-which only adds to the feeling that finding and buying a diamond can be a complicated and mysterious process.

Fortunately, diamonds are evaluated and appraised on the world market according to a set of criteria that is relatively easy to understand. The major components of these criteria are:

• Cut and shape
• Color
• Clarity
• Carat weight

The value of diamonds is in part due to their durability. Diamonds are uniquely resistant to both steel and fire; a diamond can only be cut or polished by another diamond. Despite this, daily wear can cause dirt to accumulate on and around a diamond, dulling its appearance. Because of this, it is a good idea to have a jeweler professionally clean your diamond and check the prongs for looseness once a year. In addition, you can use a solution of one part ammonia and six parts water to clean your diamond at home. Gentle scrubbing with a soft brush (such as a toothbrush) should loosen most dirt and greatly increase the brilliance of your diamond.