Carat determines the weight of a diamond with 1 carat being equivalent to 200 milligrams or 0.2 grams. One carat is also divided into 100 points. These points are used for describing increments of weight within a carat.
A diamond's price per carat increases in proportion with the size of the stone. Two diamonds of the same weight can have different values based on their color, cut and clarity.
More light passes through diamonds that display little color, creating a prism-like effect. If the stone is totally transparent, it becomes rarer; however, notable exceptions are fancy colored diamonds such as yellow, green, blue and pink. Grades are allocated to a diamond according to the level of color it possesses.
Based on the color scale established by the GIA (Gemological Institute of America), a letter is assigned to the degree of colorlessness found in diamonds. Starting from D and ending with Z, each descending letter denotes an increasing amount of light (yellow, brown or grey) in the diamonds.
|D||D is the highest colour grade attributed to a diamond, denoting that the stone is completely colourless (white)|
|E, F||A gemologist can identify traces of colors found in the diamond even though the stone looks colorless|
|G, H, I||These diamonds look almost colorless because untrained eye cannot notice the hint of color present in the stone|
|J, K, L||These stones have faint traces of color|
|M-Z||Color in the diamond is obvious even to the untrained eye|
Clarity is the degree to which a diamond is free from inclusions and blemishes, which can hinder the light as it passes through your diamond. Diamonds have natural "birthmarks" that vary in size, shape, position, quantity and color.
These birthmarks, or inclusions and blemishes, are formed deep in the earth during the diamond's growth. Blemishes can also result from the diamond cutting process.
A grading system has been established by the GIA for measuring the type and size of these impurities:
|FL , IF||Flawless and internally flawless|
|VVS1, VVS2||Very Very slight inclusion that is hard to view under 10x magnification|
|VS1, VS2||Very Slight inclusions that are visible under 10x magnification and may not be visible to the naked eye|
|SI1, SI2||Slight inclusions that are visible under 10x magnification and may not be visible to the naked eye|
Cut refers to a diamond's shape and more importantly to its proportions. A well-proportioned diamond brings out the maximum beauty. A diamond cut too deep or too shallow loses light through the side or bottom, resulting in loss of brilliance.
An ideal cut diamond has maximum brilliance that is achieved through exact calculation of the proportion and symmetry of the diamond. Brilliance reflecting out of the table of the diamond makes it so alluring.
Brilliant cut diamonds have 58 facets, 33 on top and 24 at the bottom and the culet. In this cut, all 58 facets appear to radiate from the center through the top of the diamond. This is the most common diamond cut.
Step cut resembles stair steps due to the three concentric rows of facets arranged around the table, culet and pavilion. Emerald cut is a good example of a step cut diamond.
Mixed cut diamonds combine the step cut and brilliant cut. For instance, the crown of the diamond can be cut as a brilliant cut and the pavilion as the step cut.