Let’s look at Clarity. Natural diamonds are the result of carbon exposed to tremendous heat and pressure deep in the earth. This process can result in a variety of internal characteristics called ‘inclusions’ and external characteristics called ‘blemishes.’

Evaluating diamond clarity involves determining the number, size, relief, nature, and position of these characteristics, as well as how these affect the overall appearance of the stone. If you are trying to determine what is the best clarity for a diamond, remember that no diamond is perfectly pure. But the closer it comes to purity, the better its clarity.

Diamonds are renowned for their ability to transmit light and sparkle so intensely. We often think of a diamond’s cut as shape (round, heart, oval, marquise, pear), but what diamond cut actually does mean is how well a diamond’s facets interact with light. Precise artistry and workmanship are required to fashion a stone so its proportions, symmetry and polish deliver the magnificent return of light only possible in a diamond.

Achieving the best cut for a diamond reflects in the stone’s final beauty and value. And of all the diamond 4Cs, it is the most complex and technically difficult to analyze. To determine the cut grade of the standard round brilliant diamond – the shape that dominates the majority of diamond jewelry – GIA calculates the proportions of those facets that influence the diamond’s face-up appearance. These proportions allow GIA to evaluate what the best cut for a diamond is, by studying how successfully a diamond interacts with light to create desirable visual effects, such as:

Diamond shapes on the finger by carat size

Cushion Cut

GIA Diamond Grading Report includes an assessment of a diamond’s 4Cs – color, clarity, cut, and carat weight – along with a plotted diagram of its clarity characteristics and a graphic representation of the diamond’s proportions. For standard round brilliant cut diamonds falling in the D-to-Z color range, the report also includes a GIA Cut grade. The GIA laboratory issues diamond grading reports for loose, natural diamonds in the D-to-Z color range that weigh 0.15 carats or more. GIA Diamond Grading Reports are not issued for laboratory-grown diamonds, diamond simulants, mounted diamonds or those that have undergone unstable treatments, such as fracture filling or coating. And while reports may be issued for diamonds that have been laser drilled or HPHT processed, reports will indicate that the diamond hae been laser drilled or HPHT processed, reports will indicate that the diamond has been treated.

Color: What does 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.

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.

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.’

All else being equal, diamond price increases with diamond carat weight because larger diamonds are rarer and more desirable. However, two diamonds of equal carat weight can have very different values (and prices) depending on three other factors of the diamond 4Cs: Color, Clarity, and Cut.

While now you know what carat means, it’s also important to remember that a diamond’s value is determined using all of the 4Cs, and not just carat weight.