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Diamonds: Brief History and Understanding

A Diamond is one of the best-known and most sought-after gemstones for engagement rings. However, very few engagement rings actually featured diamonds before the 20th century - rings would feature popular gemstones of the time including emeralds, rubies and sapphires. But in 1947, 'De Beers' (a group of companies which have leading roles in the exploration, mining, retail and trading of diamonds) feautred a new tag line in the advertisement of their engagement rings. By 1990, 80% of engagement rings would have a sparkling diamond at their centre. But how exactly do diamonds sparkle so exquisitely?

Diamonds are, infact, rather dull in their nature. Their sparkling quality is a direct result of the way in which they are cut by the jeweller. But it was in 1919 when a young physicist named Marcel Tolkowsky perfected this intriguing arcane art. Having studied diamond optics with the aim of maximising sparkle, Tolkowsky discovered the world-renowned, 57-facet "brillaint cut" - the quintessential shape in which almost all diamonds are cut today.

The 57 facets in the brilliant-cut diamond create an immense number of internal pathways along which light entering the stone can travel. The light that appears to pour from a diamond under certain lighting is the result of Tolkowsky’s pattern bouncing light around. His work maximises two key aspects of a diamond’s shine – brilliance and fire.

Brilliance is a measure of the white light that beams from some facets of a diamond. When lit directly from above, light entering the diamond strikes one lower facet, and then a second, at near-perfect 45-degree angles (see illustrations below). This reflects the light back out the top of the stone, so that to the viewer it seems light is streaming from inside the diamond. If the diamond’s cut is angled too steeply then the light is reflected out the side of the stone. Too shallow, and it exits out the bottom.

The Way a Diamond Handles Light


As Newton discovered in his experiments with prisms, white light is a mixture of all the colours in the rainbow - and that by refracting it, these component colours can be separated out. This effect, which generates the little rainbows of colour that diamonds create, is called chromatic dispersion - or in gemmological terms, "fire". Light striking a diamond at an angle gets refracted, or bent, as it enters the stone and creates this second key element to the alluring diamond sparkle. 

Diamond Brilliance and Fire


There’s one final element to a diamond’s sparkle – and it relates not to light, but to darkness. Unless a diamond is evenly illuminated from all sides then not every facet will be lit up. Dark objects in the stone’s surroundings will also be reflected in the stone’s surface, making some facets appear dark. Your pupil, for example, is a very dark object, so when you look closely at the dark areas in a properly cut diamond you are seeing into the depths of your own eye!

Why is the diamond’s dark side so important for its sparkle? The most compelling reason our eye is caught by the sparkle of a diamond resides in the brain. Parts of the visual cortex respond strongly to high intensity contrast edges, and so the close proximity between brightly lit and very dark facets enhances the perceived brilliance of a diamond. The visual impact is enhanced by any slight movement of the stone, which causes a dramatic flashing and different facet areas to light up and then dim. Other areas of the visual cortex are set off by sudden changes in brightness. These areas alert the frontal regions of the brain to get our attention, which is why diamond sparkle is so arresting.  And once captivated, the emotional connotation areas of our brains may kick in with the symbolism and associations of the stone.

But we also recognize diamonds for their outstanding physical qualities. Most notably, diamonds have the highest hardness and thermal conductivity of any material. 

Most natural diamonds are formed at very high temperatures and great pressures at depths of 140-190 kilometers in the earth's mantle. Carbon-containing minerals provide the necessary carbon for a diamond to be produced, and the growth of the material occurs over periods from approximately 1 billion to 3.3 billion years. 

Diamonds are used in jewellery because of their unrivalled beauty and rarity. A diamonds is an investment - a unique token of emotional connection.

Evaluating a Diamond's Quality

A Diamond’s value is based on the four C’s: Colour, Carat, Cut and Clarity. They are also available in many different shapes to satisfy each individual's preference in style for their unique diamond jewellery. 

Diamond Shape


Diamond shapes have different attributes, but overall the beauty of the individual shape of a Diamond is a matter of personal taste. The brilliant-cut diamond (round shape) is one of the most popular diamond shapes available. 


Diamond Colour


A diamond’s colour grade refers to the lack of colour i.e. Diamonds that are white (containing little or no colour) receive the highest quality grades.


Diamond Clarity

Almost every diamond will consist of some tiny imperfections. Diamonds with few or no imperfections are rated highest in clarity. Diamond clarity ratings range from FL (best quality) to I (poor quality):



                 * (10X) refers to the visibility of inclusions under ten times magnification

FL (Flawless): No inclusions or blemishes are visible to a skilled grader using 10× magnification.
(Flawless diamonds are rare and extremely expensive)

IF (Internally Flawless)No inclusions and only blemishes are visible to a skilled grader using 10× magnification

VVS (Very Very Slight Inclusions)Inclusions are difficult for a skilled grader to find under 10× magnification

VS (Very Slight Inclusions): Inclusions and external blemishes are minor and difficult to find under 10x magnification

SI (Slight Inclusions): Inclusions and external blemishes are easy to locate under 10x magnification

I (Inclusions): Inclusions and/or external blemishes are quite visible with the naken eye and may affect transparency and diamond brilliance


Diamond Carat


A Diamond’s Carat is specifically a measure of a diamond’s weight.

One carat is equal to 0.2grams.


Diamond Cut – The Most Important Factor


Each diamond gets its unique sparkle and brilliance when the maximum amount of light enters and reflects back out of the diamond. In order to achieve this, a diamond must be cut to ideal proportions so that the light is reflected from one surface to another and then dispersed through the top of the stone. The light deflected externally will amplify and disperse the deflected light from within to provide a myriad of colours and an even concentration of light, brilliance and shine.

To put it simply, the better a diamond is cut, the more sparkle it will have.