How a diamond is cut determines the amount of light it can reflect back out to your eye, it’s sparkle. The diamonds cut grade level from poor to excellent is determined by the expertise of the cut, the depth, accuracy of the cut so that the diamond can reflect the best possible spectrum of light.

A diamonds color rating is determined by the lack of complete color within the diamond. Some diamonds are more yellow while those in the rating of D-F are colorless. See below for examples of the rating level and example of how much color or yellow is in each level.

Clarity of the diamond is determined by how many particles are in the diamond. Think of it like specks within the diamond. There are diamonds without any specks, those are flawless, while others have varying levels of specks.

Diamonds are weighed in metric carats. Diamonds which are the same carat weight can cost differently based on their cut, clarity and color. See the example below of sizing, this is not to scale as your computer or smartphone can reduce this image size but it is a good approximation as to the proportion differences.