When choosing a diamond it is important to understand the language that describes them. This grading guideline was created by the GIA (Gemological Institute of America) and the accompanying short videos by GIA will help you understand the 4 C's of a diamond.
Carat: The carat is a reference to the diamonds weight, not it’s size. Due to the proportions and cut of a diamond, it is possible for two of the same carat weight to vary in shape and size. The use of the word carat actually comes from the word carob. In ancient times carob seed was known to have a fairly uniform weight and were used by traders to balance the scales when weighing gems. In 1913 the United States adopted the standard measurement of .2 grams per carat, today this measurement is standardized around the world.
Cut: is what gives a diamond its brilliance. This guideline is more concerned with the proportions of the diamond versus the shape. A “well-made” stone is one with the precise cuts and facets to allow maximum light to enter, resulting in the beautiful shine we associate with diamonds. The result of the light entering the diamond and reflecting back to your eye is broken down into three factors:Brightness: the combination of all white light reflecting from the diamondFire: the flares of color emitted from a diamond Scintillation: the flashes of light that occur when the diamond, the light or the observer moves
Color: When assessing color of a diamond what you cannot see is the most important. While almost all diamonds (not including fancy colors) are considered “colorless,” upon examination will contain tinges of yellow or light brown. Color is rated from D (completely colorless) to Z (light yellow). A truly colorless diamond is a rare find. Almost all diamonds contain some color, but the gradients are so slight it takes a highly trained eye to grade the difference.
Clarity: The clarity of a diamond is determined by the number and location of flaws or blemishes it contains when viewed under 10x magnification. These naturally occurring events are a result of the intense pressure and heat present when a diamond is formed. Another result of this atmosphere is the inclusions or “birthmarks” of a diamond. This characterization can also act as a way to identify the diamond, as no two naturally occurring stones contain the same inclusions. The clarity classification chart is as follows: