The 4Cs refer to the four main characteristics used to evaluate the quality and value of a diamond. They stand for Carat, Cut, Colour and Clarity.
Carat
This is the measure of a diamond's weight, and by extension, its size. Five carats equal one gram. Each 100 for the carat is expressed as a point. Generally, the larger the diamond, the more valuable it is, but size is not the only determinant of value.
Cut
This refers to how well the diamond has been cut from its raw form. Factors like the depth and symmetry of the cut, as well as the diamond's overall proportions and ability to reflect light (brilliance), are evaluated. The quality of the cut greatly impacts the diamond's sparkle and aesthetic appeal.
Colour
This measures the degree to which a diamond is colourless. The Gemological Institute of America (GIA) grades diamond colour on a scale of D (colourless) to Z (light yellow or brown). Colourless diamonds are rare and therefore more valuable.
Clarity
This assesses the presence of internal or external flaws, known as inclusions and blemishes, respectively. The GIA's clarity scale includes eleven grades ranging from Flawless (no inclusions or blemishes visible under 10x magnification) to Included (inclusions and/or blemishes visible to the naked eye). The fewer inclusions or blemishes, the higher the diamond's clarity and value.
Remember that the perfect combination of these 4Cs would ideally lead to the most valuable diamond. However, preferences can vary greatly from person to person. Some might prioritise size over perfect clarity, while others may prefer a flawless smaller diamond. Therefore, the best diamond is one that matches your personal taste and budget.