CARAT
Diamonds are weighed in metric carats and each carat is equal to 100 points. A .75 carat diamond is the same as a 75-point diamond or a three-quarter carat diamond. It's not just a diamond's carat weight or size that makes it valuable, but a combination of the four c's.
COLOR
Diamonds are actually valued by their lack of color. This means that the less color a diamond has, the higher the value. They are graded on a range from D to Z, with D being colorless and Z being a yellowish color. Letters D to F are considered colorless, G to J are considered near-colorless, K to M are faint yellow, N to R are very light yellow and S to Z are light yellow.
CLARITY
Diamonds are formed deep beneath the surface of the Earth under extreme heat and pressure. Because of this, it’s perfectly normal for a diamond to have internal and external imperfections, known as blemishes and inclusions. Blemishes are found on the outside of the diamond, while inclusions are on the inside. Both affect clarity because they can interfere with the way light passes through the diamond. When there are many imperfections, the stone may appear murky. It’s extremely rare to find a flawless diamond that lacks these inclusions, but they are not always visible to the naked eye and can sometimes only be seen through 10x magnification. The grading scale for clarity ranges from flawless (F) to very very slightly included (VVS), very slightly included (VS), slightly included (SI) to included (I).
CUT
The cut of a diamond is often mistaken for the shape of the stone. However, it actually takes into account the diamond’s proportion, symmetry and polish, giving a diamond its sparkle. The GIA grades cut by Excellent, Very Good, Good, Fair and Poor. An Excellent graded stone will shine brilliantly without any dark spots.