A diamond is bought on four important criteria, known as the 4Cs - color, clarity, carat weight and cut. Each criterion plays an important role in determining the price and quality, however, you may place more or less importance on any of Cs depending on your personal decision.
Though a colorless diamond is considered most valuable, diamonds do have some degree f color in them, even though they may appear colorless.
A diamond’s radiance is on account of the cuts. Cuts are the arrangement of facets in the stone. Cuts that affect the beauty and the cost of the diamond are determined by human skill rather than nature. It is seen by most as the most important of the 4Cs.A diamond cutter will follow precise mathematical proportions relating to the height, width and depth of the crown (top), girdle (widest part) and pavilion (bottom). When a diamond is cut to the right proportions, light reflects from one facet to another and then disperses through the top of the stone, resulting in a burst of fire and brilliance. Fire is the flashes of color one sees when you look at a diamond; brilliance is its sparkle.Learn more about Diamond Cut
A color scale established by the Gemological Institute of America (GIA) assigns a letter to the degree of colorlessness found in a diamond. Beginning with D and ending with Z, each descending letter denotes an increasing amount of light yellow, brown or gray in the diamonds.
D, E, F : The stone appears colorless. However a gemologist can identify the minute traces of color found in these diamonds.
G, H, I : These diamonds have a hint of color that is not noticeable to the untrained eye. Almost colorless
J, K, and L : Faint traces of color are visible when the diamond is looked at face up.
M – Z : The color in the diamond is obvious even to the untrained eye
It is almost impossible to have a diamond without impurities. Often invisible to the naked eye, these natural blemishes are categorized as — inclusions, which are internal, and blemishes, which are external. When the stone was being formed sometimes trace elements or minerals get trapped that result in inclusions that appear as feathers, clouds or crystals. Scratches and chips visible to the naked eye are known as blemishes. While fewer such impurities will make the diamond more valuable the diamond, higher clarity does not necessarily mean that the diamond is more beautiful than a stone of a lesser clarity. But it will make a difference in terms of how the diamond is priced. The GIA established a grading system to measure the type and size of these imperfections
FL, IF : Flawless, Internally Flawless. There are no inclusions — internal flaws — or blemishes — external flaws.
VVS1, VVS2 : Very, Very Slight Inclusions. Hard to view such inclusions under 10x magnification. An excellent quality diamond.
SI1, SI2 : Slight Inclusions. Inclusions are visible under 10x magnification and may not be visible to the naked eye when the stone is in the face-up position.
I1, I2, I3 : Obvious inclusions, which are visible to the naked eye.
The size of a diamond is measured, not by its dimensions, but by weight. One carat, the traditional unit of measure for diamonds, is equal to approximately 0.2 grams. You may also hear the weight of a diamond referred to in points. A point is equal to 1/100 of a carat; therefore, a 75-point diamond equals 0.75 carat. Diamonds of equal weight may appear slightly different in size, depending on their depth and proportions. Because they are quite rare, larger diamonds of gem quality are much more valuable.Learn more about Diamond Carat