The 2nd C of Sapphires: Clarity

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Sapphire clarity is one of the more interesting and often overlooked aspects of sapphire quality, as colour is one of the most significant factors when it comes to measuring sapphire quality. Hence the visual purity of the stone, which is based on the absence or the lack of blemishes within, tends to be valued less in contrast to the others. However clarity in gemstones is a key marker of value, and sapphires, unlike diamonds provides new challenges when it comes to their study. When it comes to understanding sapphire clarity it is best to start by understanding how this concept applies first in the world of diamonds. Like anything related to gemstones, diamonds hold the top position when it comes to the study of precious stone, and in terms of value, how the variable of clarity is applied to determine value in diamonds is the place to start, helping us to then make sense of how clarity applies to sapphires.

The 4Cs: Diamond Clarity

As one may know the 6Cs of Sapphires is partly based on the fundamentals of the 4Cs, established by the GIA. The 4Cs of diamonds measures a diamond’s value by analysing its quality in relation to its: Colour, Clarity, Cut, Carat. Diamond clarity refers to the absence of inclusions, which may take the form of impurities and other imperfections that exert a negative effect on the visibility of colour in the stone. Which in the context of carbon-based gemstones pertains to the lack of it: since the colour is an undesirable trait in diamonds, the presence of a colour (i.e. in the form of brown or yellow shading) is viewed as having a negative impact on the stone’s clarity and colour. However pronounced imperfections that affect the character of the gemstone, assert a negative effect on the stone’s interaction with light-on and within the diamond-in turn affecting the stone’s grading. Since diamonds are valued for their colourlessness, the prevalence of these inclusions affect the scintillation, brilliance and other factors that measure a diamond’s interactions with light, notably white light. The grading of diamonds with respect to clarity goes from Flawless / Internally Flawless (FL/IF), Very Very Slightly Included (VVS1/VVS2), Very Slightly Included (VS1/VS2), Slightly Included (SI1/SI2) to Included (I). Diamonds that fall below the Very Slightly included mark are often not considered suitable for fine jewellery, owing to the noticeable presence of visible inclusions to the naked eye.

Inclusions vs Blemishes

A related but often overlooked point when it comes to measuring diamond and gemstone quality is the type of factors that adversely affect their clarity. When the clarity of a diamond is analysed it is usually done with the aid of a 10x microscope. A necessity when it comes to distinguishing between diamonds that fall under the category of Flawless (FL) and Internally Flawless (IF). Since both Flawless and Internally Flawless diamonds contain no visible inclusions or blemishes to the naked eye. However, upon microscopic viewing, Internally Flawless (IF) diamonds show visible blemishes (i.e. on the surface of the diamond) but no inclusions like the Flawless diamonds, despite both diamond types having identical clarity within the stone. The various types of these blemishes also apply to sapphires, which will be engaged below. Now we shall see how the factors that gemstone clarity differs with respect to sapphires in contrast to diamonds.

Inclusions and How Sapphire Clarity is Different

As noted, colour is a key variable in sapphires. Unlike diamonds where the transparent character of the stone and its ability to interact and reflect white light is viewed as topmost in importance. In sapphires, the capacity of the gemstone to emanate colour is the key factor. So the factors that affect the clarity of the stone, also invariably affect its colour. With respect to inclusions, since sapphires are conundrum based minerals, unlike diamonds, the colour that is present in them is due to the presence of external factors. Chemical elements that depending on the level and region of concentration will come to affect the clarity of the stone. Notable among them is the variety of mineral inclusions, also known as needles. These fine needle-like features occur due to the mineral rutile (mineral oxides) that form within the gemstone, affecting its clarity and the purity of its colour.

Other clarity adverse factors are minor breaks within the gemstone, the zoning of colours: a notable feature in sapphires where colour becomes concentrated in one area, leaving the rest of the stone less vivid, or one area of the stone darker and less visible. Interestingly, when it comes to sapphires, not all inclusions are bad. For example, the now out of market Kashmir sapphires, once considered to be the most valuable variant of the blue sapphire, was known for their velvety texture: a distinctive tint of blue that made the stone stand apart from the competition. This velvet tint was the result of the very same inclusions, only this time there were of the immensely microscopic variety, which upon interaction with light produced a highly desirable effect.

Sapphires depending on the quality and carat of the stone tend to carry inclusions. Top-quality stones, like the prestigious blue sapphire, that come with solid colours typically contain fewer inclusions and hence have better clarity than other sapphire variants. Blue sapphires with perfect clarity are rare, and often blue sapphire variants which such a high level of clarity, tend to be found as uncut gemstones, with much larger carats (i.e. over 5 carats), and tend to be viewed as speciality stones; commanding high prices. Further certain types of sapphires, like the famous Cornflower blue sapphire, besides their rarer shade of blue, tend to be associated with a higher level of clarity.

Types of Sapphire Inclusions

Since sapphire is of different mineral character to those diamonds, the kind of inclusions that are found within them tends to be different. From crystals, which are solid forms that appear within the internal structure of the stone. Silk needle inclusions which we spoke of earlier, are made of titanium dioxide (rutile) and other minerals that produce silk-like lines. As noted, when it comes to sapphires not all inclusions are bad, with silk inclusions, depending on where they form and their concentration is at times preferred in corundum gemstones, including rubies. In certain sapphire types, these silk effects combine to produce an effect called Asterism, which leads to the famous Star Effect in gemstones which command a unique appeal. Other inclusion types include Needles: which are long, thin inclusions that consist of a variety of materials: crystals, or even liquids (growth tubes). To Cavities, which are miniature holes extending from the surface of the sapphires, going into its depth.

The Presence of Competing Standards for Measuring Sapphire Clarity

In the world of sapphires, given the prevalence of numerous gem companies and online jewellery sellers, many who are trying to distinguish themselves in this competitive trade have sought to put forward various standards for understanding and measuring gemstone quality. Since the standards when it comes to the world of diamonds has been firmly set thanks to the authoritative contributions of the GIA. The world of sapphires has hence been left open. Hence over the years, a number of alternate measures for determining sapphire quality in relation to clarity have emerged in recent years. This means the buyer and those interested in learning about sapphire quality have naturally been left confused. The process of accurately measuring sapphire quality in terms of clarity, which are understandably based on diamond clarity standards, raises new questions on their reliability to corundum gemstones.

At Brillioyond our approach to the study of sapphire clarity is to view it in light of other factors that contribute to the quality of sapphires. As an industry first we have developed the 6Cs of Sapphires which studies and measures the 6 key factors that contribute to sapphire quality: Colour, Cut, Carat, Country, Curing & Clarity. So the clarity of sapphire is viewed as a variable of gemstone quality as one that only makes sense in light of how well the gemstone scores in other areas of value. For example, a sapphire with very few inclusions will be less valuable if its colour gamut is poor, or is affected by colour zoning. Or if a gemstone has a relatively higher number of inclusions, but whose shortfalls are offset by a larger carat stone and with strong colours will also command a higher value in contrast to a gemstone with no inclusions, but with poor colour, and with an unsophisticated gemstone Cut. Our focus via the 6Cs is on the overall quality of the gemstone. So in relation to its clarity, this is a variable that must be viewed within the broader framework of sapphire quality. This means that adopting fancy naming, or the development of ad-hoc categories of measure is not useful in this regard.