If a diamond is virtually free of inclusions and surface markings, it will be graded as flawless. These diamonds are extremely rare and very expensive. The size, location and number of inclusions will determine a diamond's clarity rating. Clarity ratings are determined by an expert gemologist under 10x magnification. The less inclusions there are, the more expensive your diamond will be.
Cloudy fluorescence is undesirable.
On the other hand, medium to strong blue fluorescence can be an asset to diamonds that are not in the colorless range, as it will tend to enhance the brilliance of the diamond and make it appear whiter. One carat is divided into 100 points. Many people think carat-weight is the primary determination, however, it is a combination of all the above characteristics that will ultimately determine the value of a diamond. Terms and Conditions for Advertisers and Consumers .