Begin with the diamond you have in mind
At GemBox, diamonds are sourced individually, never selected from a fixed inventory. Each stone is sought through established cutting centres and long-standing relationships within the international diamond trade, according to the qualities that matter to you.
You may begin with a precise specification – or simply with an idea. Carat weight, shape, colour, clarity and budget provide the starting point; our role is to refine the search and present a selection worthy of consideration.
Every diamond is natural, cut and polished, and accompanied by an independent grading report from the GIA or another recognised laboratory.
The four characteristics
Carat weight, cut, colour and clarity – the four characteristics by which a diamond is described and assessed. Together, they form the internationally recognised 4Cs grading framework.
Yet no diamond is defined by a single grade. The four characteristics must be considered in relation to one another, alongside the proportions, light performance and character of the stone.
The most considered choice is rarely a question of pursuing the highest grade in every category. It is about finding the right balance – between beauty, rarity and value, according to what matters to you.
No two diamonds are ever alike. Each possesses its own combination of characteristics, proportions and character – making every stone uniquely its own.
The measure of a diamond’s weight – not of how large it appears.
Proportions, symmetry and polish – the way a stone interacts with light.
Graded from D to Z by the degree to which colour is absent.
A record of how the crystal grew, assessed at 10× magnification.
Two words that are not interchangeable
Shape describes the outline of a diamond when viewed from above. Cut refers to the precision of its proportions, symmetry and polish – and ultimately, to the way it interacts with light.
Shape is a matter of personal preference. Cut is a matter of craftsmanship and is formally graded. Of the four characteristics, it has the most direct influence on a diamond’s brilliance and presence.
A diamond of exceptional colour or clarity cannot compensate for poor proportions. Conversely, a beautifully cut stone can reveal remarkable life and brilliance without requiring the highest grade in every other category.
Ten shapes we source
Shape is a matter of preference – each one behaves differently in light.
Fifty-seven or fifty-eight facets arranged to maximise the return of light through the crown. Its proportions are the most extensively studied of any diamond shape, making the round brilliant exceptionally effective at revealing brilliance while helping to conceal faint colour and minor inclusions.
An elongated shape with the brilliance of a brilliant-style facet arrangement. Its extended outline can create the impression of greater size and a longer, more slender appearance on the hand. Proportions and symmetry are particularly important.
A rectangular or square shape with cropped corners and long, parallel step-cut facets. Its broad, open facets create elegant flashes of light rather than the scintillation of a brilliant cut, while revealing colour and inclusions more readily.
A brilliant-style shape with one rounded end and one defined point. Symmetry is essential: the shoulders should be balanced and the point should align precisely with the centre. The tip is particularly vulnerable and should be carefully protected by the setting.
A square or rectangular shape with softly rounded corners. Cushion diamonds can vary considerably in facet arrangement, from larger, broader facets in antique styles to more brilliant patterns in modern stones, giving each a distinctive character.
A brilliant-style shape defined by two rounded lobes and a central cleft. Symmetry is essential: the lobes should be balanced and the point clearly defined. Its delicate outline requires thoughtful proportions and a setting that protects the point.
A square or rectangular shape with cropped corners and brilliant-style faceting. It combines the clean geometry of an emerald cut with the lively light return of a brilliant cut, creating a distinctive balance of structure and sparkle.
A square step cut with cropped corners and concentric facets that draw the eye towards the centre. Similar to the emerald cut, its broad facets reveal colour and clarity readily, while its deep proportions and symmetry create a distinctive geometric character.
An elongated brilliant-style shape with a point at each end. Its long outline creates the impression of greater size for its weight and a graceful, elongated appearance on the hand. Precise symmetry is essential, with both points aligned on the centre line.
A square brilliant-style shape with four defined corners. Its faceting creates lively brilliance and scintillation, while its straight lines give it a distinctly modern character. The four corners are particularly vulnerable and should be securely protected by the setting.
Weight is not the same as size
Carat is the standard measure of a diamond’s weight. One carat equals 0.2 grams and is divided into one hundred points – a 0.50 ct diamond, for example, is a fifty-pointer. The term has its origins in carob seeds, once used as counterweights by gem traders, before the carat was internationally standardised at 200 milligrams in 1907.
Weight alone, however, does not determine how large a diamond appears. Two diamonds of identical carat weight can have noticeably different face-up dimensions, depending on their proportions. A stone cut too deep may carry excess weight below the girdle, adding to its carat weight without adding proportionally to its visible size.
Diamond prices do not increase proportionally with weight. Significant price thresholds occur at certain round carat weights, meaning a 0.95 ct diamond and a 1.01 ct diamond may appear virtually identical in size while commanding notably different prices. Where the specification allows, staying just below a threshold can be a considered way to balance size, quality and value.
Typically used as accent and side stones, including pavé.
A common range for single-stone rings, with one carat remaining a familiar reference point for a centre diamond.
Availability becomes more limited, while the price per carat can rise significantly as weight increases.
Sourced individually, according to availability and specification. At this level, rarity often becomes the defining consideration.
Graded by what is absent
Colourless diamonds are graded from D to Z according to the degree to which colour is absent. D represents the highest point of the scale; towards Z, a diamond reveals increasing traces of yellow, brown or grey. Grades are determined under controlled lighting, face down against a set of master stones – rather than in the position in which a diamond is worn.
The scale begins at D by design. When the GIA introduced the modern grading system in the early 1950s, the trade was using terms such as A, AA and AAA inconsistently. Beginning with an unused letter created a clear distinction from the classifications that came before it.
In practice, colour is considered together with the shape and setting of the diamond. A round brilliant tends to conceal lower colour grades through its faceting, while an emerald cut can reveal colour more readily through its broad, open facets. The surrounding metal also influences perception: a subtle warmth may be more apparent against platinum and far less noticeable in yellow gold.
For this reason, colour is often the characteristic where thoughtful flexibility can allow greater weight without compromising the visual impression of the stone.
Diamonds in which colour is a defining feature, rather than an absence of colour, are graded separately from the D–Z scale. Fancy colour diamonds are assessed by hue, tone and saturation, with grades ranging from Faint to Fancy Vivid and Fancy Deep. Their rarity and character place them in a different category entirely, and each is sourced individually.
A record of how the crystal grew
Clarity describes the internal features, known as inclusions, and surface characteristics, known as blemishes, formed as a diamond grows. Every diamond is evaluated at 10× magnification, and its clarity grade reflects the number, size, relief, nature and location of these characteristics. While many may be visible only under magnification, together they contribute to the overall appearance and character of the stone.
One universal system. Eleven grades.
No inclusions and no blemishes visible at 10×.
No inclusions visible at 10×, though blemishes may be present.
Inclusions are so slight that they are difficult for a skilled grader to locate at 10×.
Inclusions are observed with effort at 10×, but are minor in character.
Inclusions are noticeable at 10×.
Inclusions are obvious at 10× and may affect transparency, brilliance and, in some cases, durability.
Every diamond remains unique. The clarity grade provides a recognised framework, but it does not tell the entire story of a stone.
Two diamonds carrying the same grade may differ considerably in the nature and position of their inclusions – which is why the individual character of the diamond, together with its grading report, always deserves consideration.
Every stone arrives with its report
Every diamond is accompanied by an independent grading report, with GIA as our principal laboratory and the standard most commonly used for the diamonds we source.
GIA, or another internationally recognised laboratory – verifiable through its own records.
Where appropriate, certification from another internationally recognised gemological laboratory may also be arranged, according to the characteristics of the stone or the requirements of the client.
Each report is issued independently by the laboratory and can be verified through its records. The grading and assessment are performed entirely by the laboratory, providing an objective record of the diamond’s characteristics.
We source diamonds that are already certified, or arrange certification as part of the acquisition process. No diamond is supplied without its accompanying report.
Request a diamond
Tell us what you have in mind. There is no obligation, and no need to complete every field. If you are unsure of a particular specification, simply select no preference – we will guide you through the options and refine the search accordingly.
