Diamonds

Helen Dimmick, the Company of Master Jewellers award winning gemologist and diamond grader takes a closer look at the significance of diamonds to the industry and consumer.

Diamonds are commercially the most important of all gem species. It is estimated that diamonds account for approximately 90% of the value of gemstones purchased throughout the world.

Throughout history they have been admired by kings and worn as a symbol of strength, courage and invincibility. Today they are seen as the ultimate gift of love. But where does this association originate and what is it intrinsically that makes a diamond so important?

Gemstones by definition are rare, durable, desirable and beautiful and a diamond is the ultimate embodiment of these qualities.

In terms of rarity diamonds are notoriously difficult to find, a fact that makes them even more desirable. Once located it is even harder to then recover material of gem quality. For example, on average 250 tonnes of ore must be mined and processed to produce just one carat of gem quality diamond.

In terms of durability diamond is the hardest naturally occurring substance known to exist. In fact, the name for diamond derives from the Greek ‘adamas’, meaning the unconquerable. It is also resistant to most chemicals. It is this supreme hardness that ensures a lasting precision of cut - quite unique among
gemstones. It is the hardness that presents a challenge for faceting and requires the application of specialist cutting techniques. The precision in terms of proportions and angles with which the stones must be cut demands a high degree of skill from the diamond cutter.

Once cut we grade diamonds on what has become known as the Four C’s: colour, cut, clarity and carat; although the secret to a diamond’s value goes beyond these criteria alone. Diamonds owe their beauty to their exceptional optical properties of ‘fire’, brilliance, surface lustre and transparency.

Diamonds display a higher degree of dispersion than any other natural colourless gemstone. Dispersion is the property known as ‘fire’ and is the ability a diamond has to split a ray of light into the spectral  colours of the rainbow.

Brilliance, by definition, is the return of ‘white light’ to the surface of a polished diamond. It is the degree of brightness seen from the top of the diamond when the light has reflected through the pavilion (lower section of a faceted stone) and the surface of a diamond.

Lustre is the surface reflection effect. Because of the incredible hardness of diamonds it can take a high degree of polish which creates mirror-like reflections and gemmologically this is known as ‘adamantine’. This is also unique and is another way in which we can distinguish diamonds from its simulants (fakes).

Diamonds are also special and desirable because of their transparency. Optically we can clearly see through the stone and this allows us to appreciate their beauty and in fact diamonds are the most transparent of all the crystalline materials.

As most consumers are aware, there are four main factors by which the value and quality of a diamond is determined. The 4C’s and any combination of these factors will make it possible to understand the quality and value of a gem:-

In terms of colour diamonds can appear on two scales. The first one is the lack of colour or the degree of  whiteness. The other is the rarity and desirability of fancy colours. Fancy colours include yellow and brown, sometimes green, pink and blue and the exceedingly rare red and purple. The desirability and value of a ‘white’ diamond decreases as the depth of hue increases, but for fancy colours this is reversed. The value of fancy colours is also determined by fashion as well as rarity.

Diamonds are also graded on their clarity, or freedom from inclusions and blemishes. It is much rarer to find a stone without natural marks, blemishes or signs of growth.

Carat is the unit measure of weight of a gemstone. The name carat is derived from the name of the ‘carob’ or locust tree found in Mediterranean lands. The dried seeds of this tree were once used by  traders as a unit of weight for gems because the seeds have a remarkably consistent weight (which is about 1/5 gram). In terms of desirability, the other C’s being equal the heavier the diamond the higher the price per carat. However, this works on a non-linear scale, therefore larger diamonds are proportionally much more valuable. For example a diamond that is twice the weight of another will be more than twice the price - as it is more than twice as rare This scale also jumps at certain points which are more popular such as 0.5ct and 1ct.

Finally cut, which is the most important of all the 4C’s. Cut has the greatest opportunity to unlock the most potential out of the diamond; it is also the only factor that is influenced by man. The standard round brilliant-cut diamond remains the most popular cut for diamond, when perfectly proportioned and cut with specific angles relative to one another this will show off the optimum optical effect of fire and brilliance.  There are however, a myriad of other cuts that are equally prized for many different reasons. These are known as fancy cuts and they express the decorative and aesthetic potential of diamonds as well as the evolution of fashion and stone cutting over the years.

Efficient marketing together with accompanying advertising have played a large part in the popularity of diamonds. Rarity of larger, clean coloured and well-cut stones combined with international marketing make diamonds a desirable asset. As a consequence of this, many fakes and simulants are found on the market; although as we can see below, nothing beats the real thing.