Since natural diamonds are formed deep below the earth’s surface, under conditions of intense heat and pressure, it is but obvious that they are born with some “birthmarks”. Diamond’s birthmarks refer to the small imperfections or flaws inside the diamond (inclusions) or on the surface of the diamond (blemishes). “Clarity” is a term that is widely used today to determine the absence or presence of those imperfections or flaws in a diamond. It also establishes the size and number of imperfections present. Diamonds with few or no flaws are rare and popular and therefore the most expensive. Most of the imperfections cannot be seen with the naked eye and can only be seen under a microscope.
Inclusions and Blemishes:
Imperfections or flaws that exist inside a diamond are known as inclusions. The diamond industry terms them “internal characteristics”. The inclusions are usually formed at the time of a diamond’s creation inside the earth. There are many different types of inclusions like cavities, knots, cleavage, clouds, bearding, pinpoint, laser lines, crystals or minerals, feathers and internal graining.
Blemishes on the other hand, are flaws that exist on the exterior surface of a diamond. They usually appear during the process of cutting, polishing or setting of a diamond. Blemishes too are of many types and are classified as grain boundaries, nicks, chips, pits, breaks, polish lines, naturals, dark spots and scratches.
These imperfections affect the quality of the stone because it is these inclusions which usually disrupt the flow of light into the diamond thus, affecting the diamond’s ability to transmit and spread light.
As per the GIA, clarity grading is done under 10x loupe magnification, and are categorized as:
Flawless (FL): Diamonds under this category neither have any inclusions nor blemishes that may be visible under 10x magnification. They are the extremely rare and hence the most expensive.
Internally Flawless (IF): In this category of diamonds, small blemishes are present on the surface of the diamond. They have no inclusions that are visible under 10x magnification.
Very, Very Slightly Included (VVS): As the name suggests they have tiny inclusions which is difficult even for a skilled grader to see under 10x magnification. The VVS category of diamonds is divided into two grades, VVS1 and VVS2. The former falls under exceptional quality with one small inclusion that is visible only to a trained eye under the 10x magnification. The latter has tiny inclusions that are visible to a trained eye under 10x magnification and is slightly lower in quality than the former.
Very Slightly Included (VS): Inclusions present in diamonds of this category can be termed as minor and their visibility under 10x magnification range from difficult to somewhat easy for a skilled grader. The diamonds under this category are divided into VS1 and VS2, where VS1 diamonds are of better quality than the VS2 diamonds.
Slightly Included (SI): The inclusions present in a diamond are very much noticeable to a trained grader under the 10x magnification. They may be very easily noticeable or very easily noticeable under 10x magnification and thus divided into SI1 and SI2 respectively, where SI1 diamonds are of higher quality than the SI2.
Included (I): Inclusions are very easily and clearly visible to a skilled grader under 10x magnification. In fact, the inclusions are visible even without magnification. The inclusions affect the brilliance of the diamonds to a great extent. This category is further divided into I1, I2 and I3, where I1 is a higher clarity grade than the I2 and I3. Diamonds under I3 have large inclusions that can be easily seen.
For clarity ratings of F through VS (and some SI), inclusions are NOT visible to the naked eye. People want a diamond to look good and often can't justify the price tag that doesn't match what the eye can see. While Flawless diamonds are the most rare, a diamond does not have to be Flawless to be gorgeous and exquisite. In fact many gemologist prefer a diamond with some level of flaws guaranteeing its authenticity.