The most important thing to know about diamond clarity is that almost all diamonds have at least a small blemish or an inclusion. Natural diamonds form as carbon is exposed to enormous heat and pressure deep under the Earth’s surface. During this process, tiny crystal inclusions may become imbedded within the diamond and interfere with the clarity of the gem. These are natural blemishes, or flaws. During the cutting and polishing of a diamond, damage to the stone can occur, or even while being worn, creating surface blemishes. Some inclusions and blemishes devalue a diamond, while others have little or no affect on the overall appearance of the diamond or its value.Types of Inclusions:
Tiny crystals or foreign minerals regularly imbed within the diamond as it forms; sometimes, smaller diamonds get caught within a larger diamond! More often than not, tiny fragments of garnet, calcite, or olivine are trapped as inclusions in a diamond. Most of these inclusions can’t be viewed without magnification, however a large cluster or mass of crystal inclusions does detract from the diamond’s overall appearance. Any inclusion or mass will lower the diamond’s clarity grade and value.
Knot blemishes are crystal inclusions that appear on the surface of the diamond. Diamonds with knot inclusions are usually given a lower clarity grade since the flaw is often visible to the naked eye.
Needles are long, thin, needle-shaped inclusions inside the diamonds that look like streaks of light inside the stone. Needles often form in clusters and can be detrimental to the overall clarity and value of the diamond.
Pinpoints are small light or dark crystals that can appear by in single inclusions or in clusters within the diamond. Pinpoint clouds are significant clusters of pinpoints that create a white haze in the diamond. This cloudy zone drops the clarity grade of the diamond.
Twinning Wisps are inclusions that twist together during the time of diamond formation. These form a white strip inside the diamond, and are commonly seen in fancy-shaped diamonds.
Surface blemishes:Nicks are essentially parts where a diamond has a chipped surface. Polishing and creating an extra facet can repair small nicks, however if there are too many, it can create an unappealing surface and devalue the diamond.
Pits are tiny holes in a diamond’s facets. While some are not visible to the naked eye, a pit on the diamond’s table (see the previous blog on diamond cut) is more likely to be visible and bring down the clarity grade. Shallow pits can sometimes be polished away.
Polishing lines are markings on the diamond that are made during the cutting and polishing process. Depending on the location, the lines may affect the diamond’s appearance. Polishing lines on the pavilion of the diamond are not as noticeable as lines in other parts.
A natural is an area of unpolished rough surface on a diamond that is sometimes left along the girdle of the diamond to allow for a larger carat weight. Naturals don’t usually impact the diamond’s clarity grade if they are present only on the girdle.
Now that you understand the various blemishes and inclusions that can occur during the processes of diamond formation, cutting, and polishing, we can discuss clarity grades. The Gemological Institute of America, the GIA, grades diamond clarity on an 11-point scale. The scale ranges from Flawless (F) and Internally Flawless (FL/IF) to Included (I1, I2, I3). Depending on the visibility of the inclusions under 10x magnification, the highest clarity categories are FL/IF to VS2 categories. ‘Eye-clean’ diamonds are diamonds that have no imperfections visible to the naked eye. They offer excellent value, and are much less expensive than flawless (FL) or internally flawless (IF) diamonds, which are extremely rare and command higher prices. Diamonds graded as Slightly Included (SI) are often considered ‘eye-clean’, however the location of the inclusion is important, and may be visible and therefore not ‘eye-clean’.
Flawless or Internally Flawless: FL or IF: Diamonds of this grade are extremely rare. FL diamonds are 100% flawless inside and out, while IF diamonds contain external surface graining.
Very Very Slightly Included 1 and Very Very Slightly Included 2: VVS1 and VVS2: A VVS1 diamond would have one inclusion that is so tiny it can only be seen under a powerful microscope. This grade is highly regarded and slightly less expensive than an IF grade diamond. A VVS2 diamond has 2 inclusions that are only seen under a powerful microscope, offering a very high level of clarity at a slightly lower price.Very Slightly Included 1 and Very Slightly Included 2: VS1 and VS2: VS1 diamonds have one small inclusion or a few tiny inclusions that are ‘eye-clean’, or invisible to the unaided eye. These can, however, be located using a regular 10x magnification loupe, which can be provided by your jeweler if you so wish. These diamonds are an excellent choice, as they are ‘eye-clean’ but still less pricy than the VVS categories. Usually VS2 diamonds have a series of tiny inclusions that can only be located using a 10x magnification loupe, similar to the VS1 grade. This grade is extremely popular since it is the last grade that guarantees an eye-clean diamond.Slightly Included 1 and Slightly Included 2: SI1 and SI2: SI1 diamonds have two medium or many small inclusions that are visible to the unaided eye. A diamond of this grade can still appear almost eye clean, depending on the placement and darkness of the inclusions. These diamonds offer exceptional value for those wishing to maximize their budget. SI2 diamonds have a greater number of inclusions that are almost always visible to the unaided eye. Similarly to the SI1 grade, SI2 diamonds can appear eye-clean and come at a fraction of the price of higher quality grades.I1 and lower: These diamonds will always have inclusions that are clearly visible to the naked eye. We do not recommend choosing a diamond of I1 or lower grade.