The 4Cs in Brief

Colour

Diamond Colour Actually Means Lack of Colour

The diamond colour evaluation of most gem-quality diamonds is based on the absence of colour. A chemically pure and structurally perfect diamond has no hue, like a drop of pure water, and consequently, a higher value.  

Using a colour scale established by the Gemological Institute of America (GIA), each certified diamond is given a colour grade from D (colourless) to Z (strong yellow or brown) by comparing the stone under controlled lighting and precise viewing conditions to master stones of established colour value. Whilst colourless diamonds graded D, E or F are considered a premium range, the near colourless grades G, H or I are also considered “white” but are more affordable. 

Many of these diamond colour distinctions are so subtle that they are invisible to the untrained eye; however, these distinctions can make a big difference in diamond quality and price. An important factor to consider when selecting Colour is the type of setting you plan on using. If you plan on mounting the stone in a Platinum or White Gold setting, consider a diamond in the D-H range. Yellow Gold will be more forgiving to a less than colourless stone, but regardless of the setting, the diamond will start to appear yellow if the Colour grade is lower than about J. 

Diamonds with colours outside the normal range are classified as fancy colour. These include deeper yellows, browns, pinks, and blues. 

Read more about colour here 

Clarity

Diamond Clarity Refers to the Absence of Inclusions and Blemishes 

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, nature, colour and position of these characteristics, as well as how these affect the stone’s overall appearance. While no diamond is perfectly pure, the closer it comes, the rarer and more desirable the diamond may be and the higher its value. 

Though flawless diamonds are the rarest, a diamond does not have to be flawless to be stunning. Diamonds with VVS and VS Clarity grades represent excellent choices for both value and appearance. Most diamonds with an SI rating do not have inclusions that are visible to the naked eye and offer a more affordable option. 

Read more about clarity here 

Carat

Diamond Carat Weight Measures a Diamond’s Apparent Size

Diamond carat weight is the measurement of how much a diamond weighs. A metric “carat” is defined as 200 milligrams, although gram weight is rarely used when referring to diamonds.  

Carat weight is nearly always discussed in terms of points with 1 carat (abbreviated ct) being equal to 100 points (abbreviated pts). A diamond’s weight is usually written in decimal numbers. For example, a diamond that weighs exactly 1 carat is recorded as 1.00ct. Each one point of weight is shown as 0.01ct. This system allows diamonds to be accurately measured in weights that are either less or more than 1 carat. 

Diamonds are available in any subdivision of 100. While ½ (0.50ct), ¾ (0.75ct) or 1 (1.00ct) carat diamonds are widely offered as engagement ring options, diamonds are available in any weight measurement, for example, 0.38ct or 0.82ct. A diamond that weighs more than 1 carat will be represented as the whole number plus the subdivision to the next carat size. For example, 1.45ct or 2.69ct. 

Two diamonds that weigh the same may have different measurements. The carat weight is a guide only to the visual size of the stone. 

Read more about carat weight here