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Diamonds are forever

A Guide to Quality

Since time immemorial gemstones and precious metals have bewitched mankind with their incredible aura and their symbolism in worship, superstition, fidelity and their capacity to adorn and embellish and they probably always will.

Diamonds are a bit like people…you have to meet them face to face to really know them; buying a stone online without first viewing it in the flesh is always going to be a bit of a risk!


To judge a diamond we have the 4C’s : Carat, Colour, Cut & Clarity

In diamonds, a carat is a weight and not a size; It is important to remember that the weight of one carat is 1/5 of a gram. If we leave out the “cor blimey big”, a 1 carat brilliant cut diamond will measure approximately 6.3mm but a 2 carat stone will measure approximately 8mm and not 12mm.

1ct = 1/5 of a gram or 5ct = 1 gram.


There is a scientific basis to the inclination towards colourless diamonds. Colour in a diamond is generally caused by the presence of atoms other than carbon, and in some cases by imperfections – such as graphitisation – in the stone’s crystalline structure. In other words it is possible to contend that a D colour stone is a purer, or less adulterated, diamond than a stone of a lower colour grade.

Most gem quality diamonds are shades of white ranging from D down to H. Below that the white will show traces of yellow or brown. Unsurprisingly, the highest colours command the highest prices. Whilst the presence of colour may indicate lower purity, there is a vast difference between a poor coloured white and a natural fancy coloured yellow diamond. Yellow diamonds are yellow because of nitrogen particles trapped in the stones atomic structure. Shades of yellow are classified as fancy, intense and vivid, with vivid being the most costly.

Pinks and blues are probably the rarest of all regularly traded fancy coloured diamonds. Large fine pinks are still in very short supply and those that exist command very high prices.

Unlike yellow diamonds with their trapped nitrogen particles or blue diamonds which are blue because of boron impurities, it’s not a chemical element that is responsible for their pinkness, it has to do with the stone’s unusual crystal structure which causes the light to be refracted in such a way that the viewer sees pink. The same theory applies to brown and red diamonds too.

At the moment Aurums most beautiful coloured diamond in the shop is a fancy orange-peach trilliant cut diamond of 4.82ct, which is set into a ring.


The cut refers to both the shape of the stone and it’s proportions. The most popular cut is the round brilliant cut , developed in 1919 with 58 facets which commands a higher price than many of the other shapes such as princess cut, pearshape, oval, cushion, emerald cut, baguette cut and a number of minor fancy shapes.

The term ‘cut’ also refers to how good the proportions of the diamond are. Basically if you can imagine a rough diamond crystal, it might have inclusions in the stone or major fractures within it’s rough shape. Highly qualified diamond cutters will examine the crystal and cut the biggest size they can whilst also trying to avoid the biggest, most obvious inclusions or flaws. That is a very simplified way of looking at it, however if the price of a stone is determined by it’s size ( the bigger the better), it’s colour ( the whiter the better) and it’s clarity ( the purist the better) then the cutters will try to cut the best stone from the rough crystal they have which might have to compromise the proportions of the stone to do this.

There is an ideal proportion to a brilliant cut diamond where scientifically certain angles within the stone will give the best fire and scintillation ( or sparkle as we would all say).


Referring to the quality of the stone and the presence or absence of flaws, the grading ranges from (IF) Internally Flawless through (VSI) Very Small Inclusions to (SI), small Inclusions which are visible to the naked eye. The diamond is examined by a trained eye with the use of 10x magnification loupe. As a rough guide, if the flaws are visible with the naked eye use your budget wisely and buy a smaller, cleaner stone.

Here again the description is very clear. The best stones are the flawless ones but these are rare, and of course more expensive. A very few of our larger diamonds may occasionally be in the grouping known as SI1 but most of our diamonds do not fall below the VS2 grade.

The inclusions or flaws in a diamond are a major factor in the stone’s value when purchasing and also when trading it in, should you ever wish to do so. A relatively new development in the diamond trade has been the assumption that only the larger stones are traded with certificates. We believe that honesty wins the day so most of our diamonds over 0.50ct will have a certificate. The provenance of the certificate is vital and it is imperative that the customer is offered one from a reputable internationally recognised laboratory.

We use G.I.A, H.R.D and I.G.I, who issue fully descriptive certificates from their independent labs. However, there are labs that issue certificates with widely differing standards-beware! We recently saw a certificate that had been given to someone visiting our shop which stated that the details of the diamond were not guaranteed as correct !!!

In our opinion factors such as proportions and who the certification body is are often overlooked by people comparing diamonds and their prices. We advise that you buy from a reputable jeweller and you should see the diamond in the flesh.

Over the age’s precious stones and precious metals have acquired an aura which fascinates mankind, and probably always will.

Jeweller, precious stones and metals possess a mysterious significance, enhancing their own natural warmth and fire, and they achieve that which man himself cannot – that is to escape from time itself.

From the earliest times the scarcity of precious minerals – and the difficulties frequently attendant upon their discovery and divining from the Earth- has given them value that made them symbols of status and social standing as well as laying the foundations for investment and the roots of the economy we know today.

The sourcing and acquisition of these amazing gemstones is of extreme importance to any prospective item of jewellery. They are intrinsic to Aurum’s success and certainly only the most breathtakingly beautiful high quality stones are, selected personally by Richard and his daughter Julie, from diamond specialists in Antwerp and from visits to stone cutters in the far East.

Care for your diamonds

Diamonds do need care to keep them at their brilliant best. A clean diamond not only reflects light better but also, actually looks bigger than one that’s been dulled by skin oils, soap and cosmetics. Diamonds have an affinity for grease and should be cleaned regularly to look their best.

Conflict-free diamonds

We endeavour to insure that all materials used in our jewellery come from ethical sources and we can offer Kimberley-certificated stones which prove this. The Kimberley Process Certification Scheme (Kimberley Process or KP) is an international governmental certification scheme that was set up to prevent the trade in diamonds that fund conflict. Launched in January 2003, the scheme requires governments to certify that shipments of rough diamonds are conflict-free.

The colour grade is determined by comparison with a series of master stones, the best grade being colourless (D, exceptional white +.) Diamonds can also occur in all sorts of colours, ranging from brownish to striking yellows, pink to purple, red and blue. These are called ‘fancy colours’. Certain diamonds can react to ‘black light’ with grades varying from nil-slight-medium to strong. Beside colour, the fluorescence of the diamond is also graded.



The weight of a diamond is expressed in carats. One carat = 0.2 grams and one carat equals 100 points.


Most diamonds are colourless to slightly yellowish. The colour grade is determined by comparison with a series of masterstones, the best grade being colourless (D, exceptional white +).

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Diamonds can also occur in all sorts of colours, ranging from brownish to striking yellows, pink to purple, red and blue. These are called "fancy colours". Certain diamonds can react to "black light" with grades varying from nil-slight-medium to strong. Besides colour, the fluorescence of the diamond is also graded.


The proportions are determinative for the brilliancy and the fire of the diamond. The symmetry describes the variations of the different parameters which define the proportions. The polish described the finish of the facets. Matrix opal is where the opal occurs as a network of veins or infilling of voids or between grains of the host rock (ferruginous sandstone or ironstone). Rare seam or band opal is also found and is typically encased in ironstone.


Diamonds can be cut in various shapes (e.g. square, pear or heart). The round brilliant is probably the best known shape.

Round Brilliant








HRD Antwerp

For further information about the Diamond Chart or to find out more about HRD Antwerp please visit