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Diamonds - The 4 C's

DiamondProbably the most well known of all the gemstones is DIAMOND. Renowned for it's hardness and durability it is an ideal material for use in engagement rings which are worn everyday.

The diamonds themselves were formed over millions of years; a combination of carbon gases and immense heat and pressure deep within the earth. The first diamond deposits in India were alluvial, found in river beds and soil which became referred to as "diamond fields" in the 1600's, although diamonds had been used in jewellery as far back as the 11th Century. Diamond mining began in Brazil in 1725 after diamonds were found by prospectors looking for gold. The next discovery was in the 1800's in Africa, by which time the Tejuco supply from Brazil had been all but exhausted. It was in Africa that some of the worlds largest and most famous diamonds were discovered and the Kimberly Mine is probably the most famous mine. Around this time Diamonds were also discovered in Russia's Ural Mountains. Throughout the 20th Century, diamonds have been found in China, Australia and America, the former sourcing diamonds of such size and quality that their position as the foremost producer of diamonds is awaited by many. A total of 20 countries have yielded diamonds since records began, yet fewer than 20% of diamonds mined are actually suitable for use in jewellery with the majority being used in industry.

The first known link between diamonds and engagement rings was in 1477 when the Archduke of Austria presented a diamond ring to Mary of Burgundy although there may, of course, have been earlier undocumented presentations of engagement rings. This tradition was resurrected by De Beers during the early 20th Centry via what resulted in being the most successful advertising campaign in history.

In 1939 De Beers determined that there were four factors indicative of quality (and therefore value) of a Diamond, thus introducing The 4 C's to the world of diamonds. These are as follows:

Carat Weight

A carat was, historically, the weight of the seed of the carob plant and in 1914, presumably for matters of convenience, the US, UK and other European countries decided to introduce the metric carat which weighed 0.2 grams. This remains the standard to this day, therefore 0.2 grams are equal to 1 Carat, and there are 100 "points" in 1 Carat (hence smaller diamonds weighing 10 points which is equal to 0.10 carats.)

 

Cut

The cut of a diamond is not only the shape of the diamond but also how well cut the diamond is. Is it cut to the correct proportions to allow the light rays to enter and exit the stone in the correct way to maximise the dispersion of light from the stone? If the diamond has been cut too deeply or at a very shallow angle, the light rays cannot reflect through the stone and exit the diamond at teh wrong point, leaving dark areas. One of the first known cuts of diamond is the Rose Cut, which was introduced during the 16th Century and remained popular until the early 1900's - particularly in smaller diamonds. Unlike any other diamond cut this has no pavillion, instead resembling a faceted cabochon with every facet covering the rounded top and featuring a flat base.

 


Old Mine Cut or "Cushion Cut" diamonds were the first step towards the type of cut we recognise today. As open settings came to fruition, diamonds with greater refraction and also greater weight were developed. However unlike modern diamonds, the emphasis was focused heavily on weight rather than refraction. These diamonds feature high crowns, generous pavillions and a cullet which appears to have been severed rather than forming a more modern point.

As studies into the refractive qualities of diamonds improved, cutters altered the formations of the facets and changed the shape of the girdle from square to circular to create a cut now termed Old European. Still, the emphasis remained on retaining as much weight as possible. Settings which required a scattering of small diamonds, too tiny to be accurately cut into either a Mine or European shape were sometimes Single or "Eight Cut" which consisted of the basic profile but with only 8 facets to the crown and pavillion.

During the 20th century, mainly due to the work of Marcel Tolkowsky and the availability of machine cutting rather than hand, Diamond cutting became the focus of geometric calculations with an emphasis on creating the ideal cut to maximise fire and brilliance. From this came the modern Brilliant Cut, which remains the most popular cut to date. In fact, many of the Fancy Cuts now experimented with and used in jewellery are based on the same principles of the Brilliant, just using a different shaped girdle.

These cuts command varying prices per carat, mainly depending upon the fashions of the time and quality of the cut. However recent years have brought about a resurgence in the demand for old or antique cut diamonds and as they are in limited supply, prices are continuing to soar year on year. Whilst they may not be ideally proportioned for refraction, and are hand rather than laser cut they possess a timeless character and romantic radiance which simply cannot be captured by modern cuts. Here at Gerry & Co we stock not only the well known cuts of diamond but also new cuts such as the Lucere. The Lucere cut is a combination of the elegance of a square cut combined with the brilliance of a traditional round cut.  It is octagonal and has 25 facets on the crown and 40 facets on the pavilion, a total of 65 facets compared to 57 on a modern brililant cut diamond.

Clarity

This has been given increasing importance over the past 100 years. Typically, commercial antique diamonds were valued purely on their weight and many surviving examples have wide ranging clarity. Less emphasis was placed on hiding the inclusions or "feathers" in the cut of the gem and for this reason it is rare to find an eye clean antique cut diamond. With the birth of the ideal cut, so too came a revolution in the way diamonds were judged and graded. No longer was their ability to sparkle under candle light decreed the number one priority and as more people found themselves in the position of owning diamonds, interest in the best clarity also began to grow. The following are the levels by which all modern diamonds are judged and graded for clarity:

IF - Internally Flawless, also called Loupe Clean, no internal imperfection(s) visible to a trained eye under 10 x magnification.

VVS1/VVS2 - Very very small inclusion(s) which are very hard to detect under 10 x magnification.

VS1/VS2 - Very small inclusion(s)which can hardly be found under 10 x magnification.

SI1/SI2 - Small inclusions, easy to see under 10 x magnification but not visible to the naked eye through the crown side.

I1/P1 - Pique 1 - Inclusion(s) immediately evident under 10 x magnification, difficult to find with the naked eye through the crown side.

I2/P2 - Pique 2 - Large and/or numerous inclusion easily visible to the naked eye through the crown side and which slightly reduce(s) the brilliancy of the diamond.

I3/P3 - Pique 3 - Large and/or numerous inclusion(s) very easily visible to the naked eye through the crown side and which slightly reduce(s) the brilliancy of the diamond.

Colour

Diamonds come in many colours, the most rare being red and most common a yellowy-white. Vivid fancy colours such as pink, blue, green, canary yellow and orange command exceptional prices, and to find a natural unenhanced diamond exhibiting the above hues is incredibly rare. Tinted diamonds are sought after in their own right, with some tints more desirable than others. A diamond with a blue tinge will normally be more prized than that with a faint yellow, and a golden cognac is generally more appealing to the majority than a muddy brown. However modern trends seem to have divided the buying public into those who appreciate a hint of colour and those who demand pure white.

Similarly to vivid colours, natural White diamonds are incredibly rare and are therefore very expensive; therefore the "whiteness" of a diamond is graded in a similar way to clarity, ranging from D (Exceptional/Blue White) to Z (Tinted Colour 4):

 

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