February 9, 2023
Clarity in Sapphires

The clarity of a sapphire as a quality criterion: How important is the clarity of a sapphire?

The clarity of gemstones refers to the different types of inclusions and their effects on the gemstone. Since gemstones have many more inclusions than diamonds, the presence of these inclusions has less of an effect on the value of the gemstone than it does for diamonds.  

However, the clarity does have an impact on its beauty and therefore its quality and value. The importance of clarity in sapphire is given, but its color plays an important role. The question is where in the sapphire are inclusions visible, how large they are, and whether they significantly affect the overall beauty of the cut sapphire in the eye of the beholder.  

Sapphire Clarity Guide

How is clarity classified in sapphire?

To understand how gemstone clarity really works, you need to understand inclusions and how they are classified. Basically, the categories of inclusions are differentiated by how visible they are. This is true for the sapphire as it is for all gemstones.  

The highest purity category is "free of inclusions," also called "Eye Clean." This does not mean that there are no inclusions at all, because gemstones are natural, and as nature would have it, even the finest stones have some tiny "natural feature" that is visible under a microscope. However, it means that they are "eye clean", that is, not visible to the naked eye. In every way, this type of stone is free of inclusions; the highest and therefore best level of purity that can be achieved in gemstones.  

The term flawless gemstones "Loop Clean" is also often used, where no inclusions can be seen in the stone even at 10x magnification. However, this depends on the trained eye of the viewer to see inclusions with a magnifying glass. This terminology is derived from the clarity grading of diamonds. For colored gemstones, flawless is all but ruled out, so it does not lend itself as a serious clarity grade, even though it is often used and advertised as such when selling.  

The next category is "Slightly Included" or "Lightly Included." This refers to stones that may have inclusions that can be seen by a professional using a lens. For the most part, these stones have small inclusions that can be seen at 10x magnification but are often invisible to the naked eye.

The category of "Moderately Included" gemstones includes stones with inclusions that can be seen without aids. Although these types of stones have visible blemishes, they are generally present in a way that does not affect the beauty or overall value of the stone or affects it very slightly.  

Finally, Heavy Inclusions and Excessive Inclusions "Heavily Included" are stones with highly visible inclusions that detract from the appearance of the stone, making it significantly less attractive and one to significantly downgrade the value of the gemstone based on its clarity even if it has a beautiful color or cut, or is very large. In the case of the latter category, "Severely Included" the inclusions are so severe that they can affect the durability of the stone and thus a serious value is not given.

Inclusions in Sapphires
Source - www.gemsociety.org

Natural features in sapphires must be considered in a differentiated manner

To judge the purity of a sapphire, the size, location, quantity and general appearance of inclusions are of utmost importance. Inclusions can affect the beauty and brilliance of sapphire both positively and negatively, so it is essential to understand inclusions.  

When it comes to inclusions, the color of the sapphire also plays a role, as dark inclusions are much more visible on a yellow sapphire than on lighter inclusions. In general, it can also be stated that with intensely saturated, darker sapphires, lighter inclusions are more noticeable than with lighter shades, and vice versa.  

Also, some may find it interesting to see inclusions as a clear natural feature in a gemstone. In fact, many inclusions are also desired, but which make the overall appearance of the stone interesting and therefore also attractive, or just very small features of nature that indicate. However, it must be said clearly, that the finest and most valuable sapphires should have no or very few visible inclusions on the surface of the stone when viewed with the eye.    

Natural features in sapphires
Source - www.gia.edu

The brilliance of the gemstone affects its clarity

In most cases, a gemstone is of high clarity if it has no noticeable blemishes or blemishes that affect its appearance. In addition, the clarity of a gemstone can also be influenced by its brilliance. A stone gets its brilliance from the way it is cut. Therefore, when a stone is cut, it is important not only to remove possible inclusions but also to maximize its brilliance.  

Brilliance is best achieved when the stone has the proper depth. The depth of a diamond is its height divided by its narrowest width. The ideal depth of a gemstone is between 60% and 80%, meaning stones with a depth of 50% can be considered shallow and are unable to achieve good saturation. Similarly, stones with a large depth, such as 90%, may appear too dark, especially if they have a dark hue, to begin with.

Inclusions in Gemstones

How do natural inclusions occur in sapphire?

The purity of a sapphire develops in the very earliest stages of its formation. Sapphires form under very specific conditions in the earth's crust. They can take centuries to form due to the presence of corundum in igneous rocks that slowly cool and change over time. As these formations cool, large mineral crystals form from the magma. The slower the cooling, the larger the sapphire becomes. The conditions under which the magma cools most likely result in changes in pressure and environmental factors that cause inclusions in the sapphires.  

The presence of these inclusions and trace minerals provides the unique color and overall appearance of each colored gemstone. As a result, each sapphire is truly unique, with no two being the same, nor having the exact same internal structure.

Does a sapphire have a particularly large number of inclusions?

Depending on the type of gemstone, it may have more inclusions or be purer in appearance. For example, emeralds and rubies contain significantly more inclusions than sapphires. On the other hand, aquamarines, tourmalines, or several other gemstones are purer than the 3 color gemstones. For this reason, ruby and emeralds are more tolerant of inclusions, and even very fine stones are described as having "acceptable" inclusions.  

With sapphire, certain inclusions in the lower body of the stone which would only be seen with a magnifying glass are not relevant to its value. When viewed from above the stone, no major apparent inclusions should be visible on the table of the gem, in the center of the gem. A factor is also the size of the sapphire, with a stone with large carat weight, the likelihood of visible inclusions is much higher, and one is more tolerant, small stones should be clean.  

Clarity in Sapphire
Source - www.gia.edu

Is it possible to graduate the clarity in sapphire as in diamond?

For gemstones, one cannot go by the diamond's graduation of clarity levels. A diamond requires more precise and differentiated clarity levels, as clarity is much more important in determining its value in diamond valuation than in colored gemstones.  

While diamonds are valued for their lack of inclusions, all gemstones are expected to have some amount of inclusions due to their natural crystal growth. In terms of clarity, colored stones are generally much more riddled with inclusions than diamonds at 10x magnification. Colored stones also have many different types of inclusions.  

When evaluating the clarity of sapphire, the "eye clean" rating is the optimal clarity, meaning that no inclusions are visible to the naked eye. Eye-clean sapphires are extremely rare and valuable, especially since even the finest sapphires are unlikely to be free of inclusions even when viewed under 10x magnification. For this reason, the gradings, "slightly included" or "slightly included" are beautiful gemstones.  

The common market classification of clarity grades for colored stones gives a good orientation, but it takes some experience to correctly classify natural features as inclusions.    


CEYLONS | MUNICH stands for the finest Ceylon sapphires. A brand committed to responsible mining of Sri Lankan gemstones obtained in an ethical manner.

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