The 4 C's: Clarity

Diamonds are usually described according to what is known as the 4 Cs, which are; colour, clarity, cut and carat weight. These 4 Cs can help determine the quality and often the value of a diamond e.g. diamonds with good levels in each of these categories are usually considered to be of higher quality and value. The assessment of a diamond’s value is of course a very complex matter and may not be as straight forward as it seems, for example a diamond of low carat weight but very fine colour and clarity may be of very high worth.

Diamonds have a carbon composition; they have a cubic crystal structure and are the hardest natural mineral on earth. They have an astonishing array of attractive qualities; they have a specific gravity of 3.417-3.55 and a refractive index of 2.417-2.419, in addition to an exceptional fire, adamantine lustre and beautiful dispersion of light. Diamonds have been sought after since ancient times for their stunning characteristics. All these lovely characteristics of course make diamond the perfect choice for your engagement ring, wedding rings and eternity ring as they are the perfect balance of beauty and practicality. Today diamonds are very carefully classified according to their qualities. Most gemstones are assessed on more of a subjective level, diamonds have approximately 5,000 standards of quality, they are however the only gemstones which have a mathematically formulate scale to determine their quality. There are several grading systems that have been devised globally; the principally recognised international scale was formulated by the Gemmological Institute of America (known as the GIA).  But the 4cs grading system is what you probably know best!

4C’s :Clarity

Diamonds are transparent to opaque naturally and can have numerous flaws. In simplistic terms when determining the clarity of a diamond a grader is effectively deciding how ‘clean’ the diamond is. Clarity is a measure of the flawlessness of a gemstone both in terms of internal and external flaws. Diamond can have internal flaws which are known as inclusions, which will affect the value of the gemstone. Diamonds with fewer inclusions are considered to be of higher worth, and those without inclusions are often referred to as ‘Ideal’ and are of course quite rare.

The clarity of a diamond is graded on a scale from FL (flawless) to Iɜ (Inclusions are visible to the naked eye). A visual representation of this scale can be seen on the ‘Noble Gems International Diamond Characteristics’ sheet. It is important for you as a customer to understand this concept when choosing a diamond, as it will give you confidence and appreciation of any imperfections or virtues in the engagement ring you decide upon. When determining the grade of a diamond in this category of quality there are several details which will be examined. Diamonds can have several different types of internal flaws. Diamonds are formed under extreme conditions of heat and pressure which can cause cracks and fissures in the gemstone which can present feather-like inclusions. As the diamond crystals form they can also form concentrated clusters of crystals which can appear as wisps or specks within the gemstone. Carbon deposits can also be an issue when observing the clarity of a diamond, this does not usually affect the brilliance of the gemstone, this will however affect its price. ‘Clouds’ can also affect the clarity of a diamond; this is where there is a concentration of minute inclusions concentrated into a small area giving the appearance of a cloud-like imperfection. Another common feature can be growth or graining lines can also occur when the diamond is developing. Of course a diamond with allot of inclusions will not have the same amount of sparkle as one without, as these inclusions will block the light from reflecting out of the gemstone in the same way, which of course detracts for the gemstone’s value. A diamond grader will also look for external flaws that could affect the clarity of the gemstone. Blemishes are a common feature of diamonds, these are inclusions on the surface of the diamond which are often inherent of the rough diamond, or were even caused when the gemstone was removed from its original environment. One slightly unusual occurrence that graders have to watch out for is laser-drill holes. This is a process which is occasionally performed to remove minor inclusions in an attempt to artificially improve a diamonds value. Essentially the diamond is drilled into with a laser and some acid is put into the channel in order to dissolve the inclusion/s. Professional diamond graders must be careful to watch out for such features as they must be declared if the diamond requires a grading report.

The clarity of a diamond is usually assessed by examining the gemstone with a loupe of 10x magnification or with a microscope. Professional graders often use darkfield illumination when observing the diamond. This is a procedure which concentrates light onto the pavilion in order to reveal or ‘light up’ the inclusions.

Diamonds with perfect clarity are extremely rare and can of course be a very costly option as a result. The majority of diamonds available on the market will show some flaws when viewed with a loupe. At Harriet Kelsall Bespoke Jewellery we usually recommend to customers that they choose a diamond of Si or higher clarity, as the inclusions in gemstones of this quality or higher will not be visible to the naked eye, making them unnoticed when you are wearing your beautiful engagement ring or wedding ring. In the past the accepted standards were far more lax in this area of course; therefore recycled diamonds or antique pieces from customer heirloom pieces of jewellery are likely to have visible flaws. Of course a gemstone that is highly facetted will be more likely to mask any internal flaws in the gemstone e.g. inclusions will generally be more noticeable in cuts like a emerald cut engagement ring where the gemstone has a relatively large table on display.