Clarity, or purity, is a diamond’s ability to let in light and reflect its brilliance. Of the Four Cs, Clarity is the easiest for you to evaluate and the most straightforward to understand.
We measure the clarity of a diamond by its size and the number of inclusions and blemishes in or on it. Inclusions are interior irregularities and blemishes are exterior irregularities. These imperfections are not flaws, but rather the natural fingerprint of every diamond. Often, we can see these only under a powerful microscope or jeweller’s loupe, and they do not visibly affect the appearance or beauty of a diamond.
Inclusions are flaws such as air bubbles, cracks, and non-diamond minerals found within the diamond, which are caused deep within the earth during its formation.
Large inclusions interfere with the dispersion of light and diminish the diamond's brilliance. They also affect the durability of the diamond, reducing its resistance to fracture. Some inclusions are coloured and also influence the appearance of a diamond.
The larger or more numerous the inclusions the less valuable the diamond.
Blemishes are imperfections on a diamond’s exterior surface and include scratches, pits and chips. Some blemishes such as nicks, pits, trigons, and polishing lines—are a result of the cutting and polishing process. Depending on their location and size, most blemishes can be polished away, or the diamond can be re-cut to eliminate them.
Surface blemishes can affect a diamond’s clarity and value, but many blemishes have little or no impact on a diamond's appearance.
Blemishes typically have less impact on a diamond's value, beauty and grade since they rarely affect the strength and structure of the diamond.
Gemmologists’ grade the clarity of a diamond by examining it top-down with a 10x magnifying microscope. Imperfections located on or beneath the table of the diamond are easier to detect and affect clarity grade more than those located around the sides of the diamond. Larger marks, darker marks and deep marks will also significantly affect the clarity of the diamond.
The Gemological Institute of America's (GIA) International Diamond Grading System™ is the globally recognized standard for diamond clarity assessment. With 11 grades, the system classifies a diamond's clarity based on the nature, position and size of its inclusions and exclusions. The list below summarizes the GIA's International Diamond Grading System.
What Clarity Grade Should I Choose?
CaratLane suggests that you work within your budget to select a diamond with the least amount of inclusions and blemishes, qualities which will negatively impact the value and durability of your diamond.
Diamonds with the least amount of flaws hold the highest clarity grading. Flawless diamonds are extremely rare and considered to be the most beautiful of all diamond grades. Because they are so scarce diamond experts consider Internally Flawless diamonds (IF) to be the most valuable examples of near-perfection in the international diamond market.
Many diamond purists insist on FL or IF diamonds, believing that these diamonds are 100% flawless; however, it is important to note that this is not the case. Almost all diamonds have some flaws. FL and IF diamonds simply have no flaws detectable under 10x magnification.
While FL/IF diamonds are the rarest, a diamond does not have to be graded so to be stunning. An "eye-clean" diamond - one that has no imperfections visible to the unaided eye – is an excellent value. SI and VS diamonds are typically considered clarity grades of fantastic value since their inclusions are minor and invisible to the unaided eye.
When looking at diamonds with many facets and a highly brilliant cut, such as round brilliants, there is absolutely no visible difference between a stone that is graded flawless and one graded SI, even though the SI is 7 grades lower. It is much less rare, but no less beautiful.
Fancy shaped and step cut diamonds, such as Emerald or Asscher, are designed with fewer facets and larger tables that emphasize transparency over sparkle, and inclusions in them are easier to detect with the naked eye. Therefore, we recommend choosing a fancy shaped diamond with a clarity grade no lower than VS2.
As diamond size increases, the size of the facets also increases. Because facets are essentially windows into a diamond, the importance of purchasing a diamond with a higher clarity grade increases. For diamonds over 2 carats, a clarity grade of VS2 or higher is the safest bet for avoiding any signs of visible inclusions. In diamonds between 1 and 2 carats, clarity grades of SI1 or better will not have inclusions easily visible to the naked eye.