Like any collectable, the initial price of a diamond and its ability to increase in value is determined by its rarity. Having diamonds professionally graded is not cheap, so it is a good idea to understand as much about choosing diamonds as possible.The main factors that influence diamond prices are its cut, clarity and carat weight, all being factors of rarity.
Cut has the strongest influence on the diamonds brilliance. In a well-cut stone, rays of light entering the diamond reflect back to the eye of the observer. In a colored diamond, the unique mixture of color that the viewer experiences is termed the “face up color". The master craftman or cutter of fancy colored diamonds is an artist who uses the colored rough diamond to create a finished diamond with fire, sparkle and beauty that is an individual masterpiece with perfectly faceted dimensions and a vibrant color composition. Cutting a diamond to proper proportions will result in light reflecting from one facet (cut side) to another in a mirror like fashion that disperses through the top of the stone resulting in a display of brilliance and fire. Sometimes a cutter will sacrifice weight and size to bring out a more intense color. Radiant and brilliant cuts in rectangle, asscher, oval, heart and pear shapes are often used to maximize the color saturation and enhance the viewing of the stone. Ideal proportions, finish and symmetry of a cut are the aim of the cutter, as well as the shape of the stone.
There is a difference between cut and shape. Shape means the outward look of the diamond (such as round, radiant, oval and so on). Cut refers to the reflective qualities of the diamond and is perhaps the most important of the Four C's.