The Four Factors, known as the Four C’s affect the value of every diamond.
Carat WeightAs with all precious gems, the weight and therefore the size of a diamond are usually expressed in carats. Carats originated as a natural unit of weight: the seeds of a carob tree. These carob seeds were uncommonly uniform in weight. Diamonds were traditionally weighted against these carob seeds until the system was standardized and one carat was fixed at 200 milligrams or 1/5 of a gram. The carat is divided into 100 “points”, so that a diamond of 150 points is a 1 and 1/2 carat diamond. The larger the diamond is, the rarer it is, making larger diamonds much more valuable than smaller diamonds of equal quality.
The Color deemed ideal for a gem quality diamond is colorless or near colorless or what is more commonly referred to as “white” color. However, diamonds can have a wide range of color from white, to various yellowish tones to very dark in hues of brown and even black. A “Fancy color” is a diamond with an unusual color or intense color, including red, blue, pink, green, brown and many shades of yellow. Keep in mind there are yellow and brown diamonds that do not have a deep enough color to be considered fancy. Red is the very rarest color for a diamond. The Hope Diamond is also extremely rare and is a famous example of a diamond with a deep blue body color. Since color is subjective, it is always best to have an independent grading report to describe ‘Fancy color’ diamonds.
Cut refers not only to the shape of the diamond but also to quality of symmetry and polish. The quality of finish on a diamond is as important as color, clarity or carat weight and is often overlooked when considering only price and not beauty. During the mid twentieth century the art of cutting diamonds had been so refined that a precise mathematical formula was developed. It called for diamonds to be cut with 58 facets, each placed at a precise angle to the other. The majority of diamonds were cut with this guideline in mind but only a small percentage is actually cut to the exact formula. More recently the Gemological Institute of America (GIA) has determined, through the study of thousands of diamonds, that there are many combinations of angles and facets that create an equally brilliant diamond. A well cut diamond is recognized by its light handling qualities, maximum scintillation and the dispersion of light through the diamond. But whether you choose a round brilliant, a princess or and oval, beauty and cut is largely a matter of personal preference.
Clarity refers to the degree which a diamond is free of interior inclusions or exterior blemishes. The size and position of inclusions and blemishes affect the value of a diamond according to the degree in which they interfere with lights passage through the diamond and the degree to which any of these inclusions of blemishes are visible. While minute inclusions or blemishes (VVS, VS, or SI) reduce the cost of a diamond, they neither mar its beauty not endanger its durability. If a diamond is without inclusion or blemish under 10x magnification, it is termed flawless, the highest clarity grade. Flawless diamonds are very rare but are available.