Diamond Cut: The diamond cut is most probably one of the most important factors (a human element that is often manipulated to save as much weight of the rough diamond as possible) in how the diamond is priced, and it has a significant effect on the overall brilliance and fire of the diamond. The diamond cut ranges between excellent, very good, good, fair, and poor. For round brilliant cut diamonds, GIA assigns a cut grade, and for fancy-shaped stones such as an oval cut or a princess cut diamond, GIA has not yet finalized a grading system. However, there are important insights that we have developed for each shape of stone that you should read before buying a diamond.

Understanding what diamond color means helps in choosing the right diamond. Interestingly, the diamond color evaluation of most gem-quality diamonds is based on the absence of color. A chemically pure and structurally perfect diamond has no hue, like a drop of pure water, and consequently, a higher value. GIA's D-to-Z diamond color-grading system measures the degree of colorlessness by comparing a stone under controlled lighting and precise viewing conditions to masterstones of established color value. Many of these diamond color distinctions are so subtle that they are invisible to the untrained eye; however, these distinctions make a very big difference in diamond quality and price. Hence, it is important to get a GIA expert's opinion in evaluating the best color for your diamond.

Diamond Clarity: Clarity is one of those factors that you can play with, depending on your budget. Diamonds are formed over millions of years under intense heat and pressure and, as a result, often have impurity and inclusions; these inclusions are the natural birthmarks of the stone and are often evaluated to determine the level of clarity in each diamond. Clarity ranges between Flawless (Fl), Internally Flawless (IF), Very Very Slightly Included 1 & 2 ( VVS1/VVS2), Very Slightly Included 1 & 2 (VS1/VS2), Slightly Included 1 & 2 (SI1/SI2), and Included 1,2 &3 (I1, I2, I3). Stones above VS2 that are graded by GIA are often considered as eye clean meaning you should not be able to see any inclusions in the diamond without the aid of a jeweler's loupe. In under 1 carat stones, unless the diamond has large black crystals, SI1 and even sometimes SI2 would be considered eye clean. I-I3 are almost always not eye clean.

To put it simply, diamond carat weight measures how much a diamond weighs. A metric "carat" is defined as 200 milligrams. Each carat is subdivided into 100 'points. This allows very precise measurements to the hundredth decimal place. A jeweler may describe the weight of a diamond below one carat by its 'points' alone. For instance, the jeweler may refer to a diamond that weighs 0.25 carats as a 'twenty-five pointer.'Diamond weights greater than one carat are expressed in carats and decimals. A 1.08 carat stone would be described as 'one point oh eight carats.

GIA's 4Cs Guide app features video and interactive tools that teach you about how GIA grades color, cut, clarity, and carat weight. It explains GIA's D-to-Z color scale and how diamond color can affect value, GIA's clarity scale and how diamond clarity can affect value, the factors that affect a diamond's cut grade and the origins of the carat system