The cut of a diamond refers to its proportions. Of the 4C's, the cut is the aspect most directly influenced by man. The other three are dictated by nature. Quite often the cut of a diamond is confused with its shape. Diamonds are cut into various shapes depending upon the original form of the uncut diamond, which is referred to as "rough." Whatever the shape, a well-cut diamond is better able to reflect light. A diamond's ability to reflect light determines its display of fire and brilliance. Diamonds are usually cut with 58 facets, or separate flat surfaces. These facets follow a mathematical formula and are placed at precise angles in relation to each other. This relationship is designed to maximize the amount of light reflected through the diamond and to increase its beauty. The cut, or proportions, of a diamond is measured in percentages relative to the diameter of its girdle. The girdle diameter of each diamond is always considered 100%. Example: The girdle of a diamond measures 10 millimeters (100%). The table measures 5.6 millimeters. The total depth measurement is 6.1 millimeters. The diamond would be described as having a table of 56% and a depth of 61%. The table and depth percentages are the key to determining good proportions.
- WELL CUT - When a diamond is cut to proper proportions, light is reflected from one facet to another and then dispersed through the top of the stone.
- DEEP CUT - When the cut of a diamond is too deep, some light escapes through the opposite side of the pavilion.
- SHALLOW CUT - When the cut of a diamond is too shallow, light escapes through the pavilions before it can be reflected.
The best color is no color. Diamonds allow light to be reflected and dispersed as a rainbow of color. This light dispersion, or color flash, has no effect on the technical grading of color. The absolute finest colorless stone carries a D rating, descending through each letter of the alphabet to Z, designating a diamond of light yellow, brown, or gray. The body color may be caused by the presence of trace elements, such as nitrogen, within the atomic framework of the carbon crystal. These trace elements are so minute that they are scientifically measured in parts per million (ppm). As the color becomes more intense, the grade for color descends the scale. These gradations are so minute and precise that discerning a single grade (even by an expert) under less than ideal laboratory conditions is extremely difficult. It is always best to compare diamonds graded by either the Gemological Institute of America (GIA) or the European Gemological Laboratory (EGL) for accurate color grading. When directly comparing diamonds for color, most consumers are unable to detect a difference unless they are at least two or three color grades apart.
- FANCY COLOR - It is often surprising to learn that diamonds also occur by rare accidents of nature in shades of pink, blue, green, amber, or even red. These rarely occurring colors are referred to as fancies and are evaluated by different set of color standards. These standards take into consideration various factors such as hue and saturation. Fancy colored diamonds are the most expensive because of their extreme rarity. Some fancy colors can cost hundreds of thousands of dollars for diamonds of one carat or less!
- FLUORESCENCE - Fluorescence is not directly related to a diamond's color. This separate characteristic refers to the diamond's ability to fluoresce under ultraviolet (UV) light. Our sun emits some UV light, but it is usually not great enough to detect fluorescence. The most common source of UV is a black light. When exposed to UV light, many diamonds will give off a distinctive glowing blue coloration. Although fluorescence may be displayed in various colors, blue is the most common in diamonds. The fluorescence of a diamond is defined by its intensity as either None, Faint, Medium, Strong, or Very Strong. Although fluorescence is a characteristic that can be measured, it is seldom an issue when selecting a diamond.
The clarity of a diamond refers to the presence of inclusions in a diamond. The amount of carbon or crystallization in a diamond is how that is graded. So thus being the more carbon or crystal inclusions in a diamond the lower the quality. Inclusions are ranked on a scale of perfection, known as clarity, which was established by the Gemological Institute of America (GIA). The clarity scale, ranging from F (Flawless); IF (Internally Flawless); VVS (Very Very Slight); VS (Very Slight); SI (Slightly Included) to (I) Included is based on the visibility of inclusions at a magnification of 10x. In simpler terms when you look at a diamond and see black spots like pepper that is referred to the carbon and the cracks or feathery item that is viewed in a diamond is called a crystal inclusion. The clarity ranges from Internally Flawless meaning no inclusions to Imperfect having very many inclusions that are visible to the naked eye. The clarity of a diamond can also be somewhat like a fingerprint. No two looking exactly alike.
The carat weight of a diamond is the size of the diamond. The rarity of a diamond is greatly affected by its size. The rarity of a 1.00-carat diamond is much greater than twice that of a .50 carat. Although it only weighs twice as much, the 1.00 carat is statistically much more difficult (rare) to mine than the .50 carat.