The 4Cs of Diamonds

Cut

Cut describes how successfully a diamond’s proportions, symmetry, and polish return light. It is often the most important factor in visible sparkle.

Colour

Colour grades describe how much body colour a diamond shows. Some designs suit a bright, icy look; others are beautiful with a warmer character.

Clarity

Clarity describes natural internal features and surface marks. Many inclusions are difficult to see without magnification, so prioritise what is visible to the eye.

Carat

Carat is a unit of weight. Two diamonds with the same carat can look different in size because shape, depth, and proportions affect their face-up appearance.

Cut: look beyond the outline

Cut quality concerns how facets and proportions work together. Brilliance is white light returned to the viewer, fire is the separation of light into colours, and scintillation is the changing pattern of bright and dark areas as the diamond moves.

Do not assume every shape or report uses the same overall cut grading system. For fancy shapes, moving images and the individual facet pattern are especially useful. Polish and symmetry describe specific finishing characteristics; they do not, by themselves, guarantee exceptional light performance.

Colour: compare in consistent conditions

Where a report uses the familiar D–Z scale for colourless to light-colour diamonds, D is at the colourless end. This is different from grading fancy-colour diamonds. Read the actual laboratory terminology rather than translating unfamiliar labels yourself.

Compare stones under the same neutral lighting and against the same background. Metal colour and surrounding reflections can influence how a diamond looks once set. A face-up comparison is useful because that is how you will usually see your ring.

Clarity: position matters as well as grade

Clarity describes internal inclusions and surface blemishes. On reports using the traditional scale, categories range from Flawless and Internally Flawless through VVS, VS, SI and Included. These labels reflect examination conditions, not simply what you can see while wearing the ring.

A dark inclusion under the centre may be more noticeable than a pale feature near an edge. Step cuts can reveal features differently from brilliant cuts. Ask whether any feature affects durability, especially near a thin edge or a point that will be set under a claw.

Carat: weight versus visible size

One carat is 0.2 grams and is divided into 100 points. A 0.75-carat stone is therefore 75 points. Carat does not specify its diameter or length: two stones of the same weight can distribute that weight differently.

Compare the report’s measurements alongside a size reference. In a ring with several diamonds, total carat weight is the combined weight of those stones; it must not be mistaken for the centre stone’s weight. Ask for both figures when the design includes accents.

Use the four measures together

Make a shortlist with the outline and dimensions you like, then inspect light performance and visible colour or inclusions. Only after that should you decide whether a higher reported grade offers a difference you personally value.

Keep comparison conditions consistent. A diamond under strong spotlights can look dramatically different from the same stone beside a window. Ordinary lighting helps you understand the appearance you will live with day to day.