Marquise-cut diamond held in tweezers in front of a loupe

DIAMONDS

Light transformed into brilliance.

The diamond is among the most treasured and widely admired gemstones in the world. Its beauty arises from the interplay of cut, colour, clarity and carat weight — the four quality characteristics known as the 4Cs.

Yet a diamond is far more than these four parameters. Shape, proportions, polish, symmetry and fluorescence all help to reveal its individual character.

ANELI ANTWERP assesses each diamond as a whole — considering not only the figures in its grading report, but also the way the stone captures, reflects and returns light.

THE 4Cs

01

Cut

Cut determines how a diamond’s facets are arranged and how precisely they interact with light. It should not be confused with shape: shape describes the outline of the stone, whereas cut refers to the arrangement of its facets, its proportions and the quality of its craftsmanship.

A diamond’s light performance is defined by three main effects:

  • Brightness (brilliance) — the white light reflected from the surface and interior of the diamond.
  • Fire — the dispersion of light into the colours of the spectrum.
  • Scintillation — the sparkle and the pattern of light and dark areas visible as the stone moves.

02

Colour

Diamond colour is graded on a scale from D to Z. D represents the highest degree of colourlessness; towards Z, a yellowish, brownish or greyish tint becomes increasingly noticeable.

  • D–F — colourless
  • G–J — near colourless
  • K–M — faint colour
  • N–R — very light colour
  • S–Z — light colour

Fancy colour diamonds — those with a distinct natural colour — are graded on a separate scale, where hue, tone and saturation are the defining factors.

03

Clarity

As a natural diamond forms, internal characteristics (inclusions) and external characteristics (blemishes) may develop. These are assessed on a clarity scale, typically under 10× magnification.

The GIA system comprises 11 clarity grades, from Flawless (FL) to Included (I3).

A clarity grade alone does not determine how beautiful a diamond will appear. Many inclusions are invisible to the naked eye, so their position, size and effect on the stone’s appearance matter just as much.

04

Carat

The carat is a unit of weight, not of size.

1 carat = 0.20 grams.

Two diamonds of identical weight may appear different in size, depending on their shape, proportions and cut. A higher carat weight therefore does not always mean a more impressive-looking stone.

Three pear-shaped yellow diamonds catching the light

BEYOND THE 4Cs

The 4Cs are only the beginning.

When assessing a diamond, the following characteristics are also important:

Shape

The outline of the diamond: round, oval, cushion, emerald, pear and other shapes.

Polish

The quality and smoothness of the surface finish.

Symmetry

The geometric precision of the facets and of the stone as a whole.

Fluorescence

The diamond’s reaction to ultraviolet light. In itself, it is neither an advantage nor a flaw — it must be assessed in the context of each individual diamond.

Proportions and measurements

These reveal how the stone is constructed and how it interacts with light.

ANELI ANTWERP’S CHOICE

Natural diamonds

ANELI ANTWERP works exclusively with natural diamonds.

We do not use laboratory-grown diamonds. This is a deliberate choice, rooted in our appreciation of the natural stone’s origin, individuality and rarity.

We look beyond impressive parameters alone, seeking diamonds in which shape, colour, clarity and cut come together in perfect harmony.

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