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The True Value Of Diamonds

by Alexandra Morris Robson

A whole host of factors can affect a gemstone’s value. Size is important, of course, but the experienced gemologist will know that a whole host of other qualities will also have to be considered in order to determine just how much a particular stone is worth. Diamonds, as one of the most beloved and valuable stones, are no different and it’s worth having these factors in mind when we purchase diamond jewellery. 

What are diamonds and why are they so special? 

I have a special place in my heart for diamonds! They are truly unique among gemstones as they are the only type to be composed of a single element: carbon. A particular set of conditions must come together to form a diamond. Under a lower temperature, the same element can take the form of graphite, which of course isn’t nearly as valuable. It takes both a high temperature and a high pressure at least 100 miles below the Earth’s surface to form a diamond. 

Today, there is a universally accepted standard of describing diamonds, known as ‘the 4 C’s’ – Colour, Clarity, Cut and Carat Weight. A combination of all four of these descriptive factors determines the overall value of a diamond.

We hear the word ‘carat’ a lot, but what does it mean?

As you would expect, the larger a diamond is, the more valuable it is. Metrically, one carat is defined as 200 milligrams. The Sewelo diamond, which weighs 1,738 carats is suspected to have been sold for between 6.5 and 19.5 million dollars.

What about colour? Are coloured diamonds worth more or less than clear diamonds?

Diamond colour is based on the absence of colour. The colourlessness of a diamond indicates its level of chemical purity, hence the greater the degree of this, the more valuable a diamond becomes. The colour grading system ranks from D to Z, with D being the highest degree of colourlessness and indicating the purest types of diamond.

It’s important to note though that coloured diamonds can also be highly valuable. Although typical white diamonds can be categorised using the D-Z colour grading system, some diamonds can be found naturally coloured in hues such as blue, brown, pink, canary yellow, or even black. As the geological conditions required to produce these diamonds are rare, diamonds with distinct colourful shades are scarce and often highly sought after.

How is the clarity and cut of a diamond judged?

Clarity relates to the absence of inclusions and blemishes which can develop during the creation of the crystalline structures under high pressure conditions. Although no diamond is completely pure, the closer a gemstone is to ‘flawless’, the higher its value.

Diamonds are renowned for their ability to trap and reflect light, which gives them the ‘sparkle factor’. Consequently, precision and highly skilled craftsmanship are essential in diamond cutting to give the stones their exceptional appearance. The cut measure is based on the stone’s brightness, fire and scintillation. This allows them to be graded on a scale of excellent to poor.