Clarity is the term given to indicate the purity of a diamond. Most diamonds have minute imperfections and the clarity is the way of grading the purity depending on the number of imperfections the diamond has or does not have.
Diamond Clarity Terms
The diamond industry uses the term "internal characteristics" instead of "inclusions". For natural diamonds, the "internal characteristics" in the diamond are growth crystals that give the diamond its character and unique fingerprint. Laboratory made diamonds are somewhat different and usually contain no inclusions.
Diamond Inclusions. These are imperfections, or flaws, inside the diamond.
Tiny spots of white, black, or other colors.
Cracks. You can get cracks in diamonds, some cause no problems at all. Others can cause the stone to split.
Colored and uncolored crystals.
Flaws on a diamond's exterior surface.
Many exterior flaws are the result of poor cutting and polishing process.
Basic diamond terms can also be found at Diamond Glossary
How Diamond Clarity is Graded
GIA clarity grading is generally done under 10x magnification with darkfield illumination. The GIA Gem Trade Laboratory, uses a binocular stereo microscope as standard equipment, able to zoom to higher magnifications when required.
These microscopes are equipped with darkfield illumination, as well as an ultraviolet light filtered overhead light. When grading is performed using a 10x handheld loupe, "darkfield" illumination is more difficult to achieve. The grader must use a light source in such a way that the base of the stone is lit from the side, and the crown of the stone is shielded from the light.
After the diamonds is thoroughly cleaned, the diamond is gently picked up using tweezers in a girdle-to-girdle hold. The grader views the diamond for the first time through the table, studying the culet area of the stone for inclusions. The diamond is then set down, and picked up with the tweezers in a table-to-culet hold. In this position the diamond can be studied from the pavilion side, and the crown side, examining the diamond through each facet for inclusions.
Once a sector of the diamond has been thoroughly examined the grader rotates the diamond using the tweezers, so that the neighboring sector can then be examined. The grader uses darkfield lighting (This is secondary light that has reflected off other objects rather than using a direct light source) to reveal characteristics, and alternatives to reflected, overhead lighting to find out if a characteristic lies either within the stone or on the stones surface, or both.
If the grader is using a stereo microscope, they may zoom in to a higher magnification to make closer observations of an inclusion, but then return to 10x magnification to make an assessment of it's impact on the clarity grade.
If a stereo binocular microscope has been used, a final assessment using a 10x loupe is performed before the final judgment is made on the clarity of the stone. The grader firstly decides the clarity category of the diamond using the keywords; none (FL, or IF if blemished), minute (VVS), minor (VS), noticeable (SI), obvious (I). The decision is then made on the grade of the diamond.
Diamond Clarity Grading
The grading scale is as follows:
IF would have no inclusions and be internally flawless, perfect clarity in other words.
Both grades VVS1 and VVS2 would be very very small inclusions, pin pricks in fact.
VS1and VS2 are still very small and difficult to see.
SI1 and SI2 would be tiny but easily seen.
I1 is small and recognisable immediately.
I2 and 13 would have larger and/or numerous inclusions, obvious recognisable immediately
There is also third pique (pronounced peekay) sometimes written as p3.
Any flaws in Diamonds can include external blemishes also from natural causes as well as from poor polishing. Most blemishes and inclusions are small enough to have no or little effect on the beauty of the diamond.
Most inclusions you find diamonds do not affect the diamonds' performance or structural integrity. However, where you get large clouds this can affect a diamond's ability to transmit and scatter light. This reduces the quality and the demand for and so the price of the diamond. Large cracks close to or breaking the surface will reduce a diamond's resistance to fracture also.
Naturally. diamonds with higher clarity grades are more valued, with the exceedingly rare "flawless" graded diamond fetching the highest price. However, minor inclusions or blemishes can be useful, since they may used as identifying particular diamonds rather like a fingerprint.
Also, as synthetic diamond technology improves and distinguishing between natural and synthetic diamonds becomes more difficult, inclusions or blemishes can be used as proof of natural origin.
Diamond Inclusions and Blemishes
The diamond industry uses the term "internal characteristics" instead of "inclusions". For natural diamonds, the "internal characteristics" in the diamond are growth crystals that give the diamond its character and unique fingerprint.
There are several types of inclusions and blemishes, which can affect a diamond's clarity in varying degrees. Also some features resulting from diamond enhancement procedures, such as laser lines, are also considered inclusions and/or blemishes.
Included crystals or minerals
Diamond Clarity Enhancement
Laser "drilling" involves using a laser to burn a hole to a colored inclusion, followed by acid washing to remove the coloring agent. The clarity grade is the grade after the treatment. The treatment is considered permanent.
GIA, as a matter of policy, does NOT certify clarity-enhanced diamonds. If you see a GIA Diamond Report with the words "clarity enhanced" or "fracture-filled," it is surely a counterfeit report.
Clarity can also be "enhanced" by filling the fracture much like a car windshield crack can be treated. Such diamonds are sometimes called "fracture filled diamonds". If this has been done it should be disclosed and reputable filling companies use filling agents which show a flash of color, commonly orange or pink, when viewed closely. There can be a significant price discount for fracture-filled diamonds.
One important point is that the treatment is not permanent or as long lasting as the diamond and the GIA will not grade fracture-filled diamonds for this reason. Reputable companies often provide for repeat treatments if heat causes damage to the filling. The heat required to cause damage is that of a blowtorch used to work on settings, and it is essential to inform anyone working on a setting if the diamond is fracture-filled, so they can apply cooling agents to the diamond and use greater care while working on it otherwise cracks may appear in the diamond and its value will be heavily reduced.
So diamond clarity is important to consider when buying diamonds. A Diamond with no imperfections or inclusions would be a top grade diamond and would be classified as internally flawless (IF). It would be extremely rare and would command a much higher price than one which has many recognizable imperfections.
But when you read the detailed explanations for each clarity category, you see that the flaws usually cannot be seen by the naked eye without magnification, even by an experienced jeweler.
Most of the tiny imperfections do not affect a diamond's brilliance and it is not until you reach the bottom level of "I" categories that imperfections begin to detract from the beauty and the price of the diamond.
So do not be concerned too much if the clarity of your diamond is not near the top of the scale. Indeed, it can a characteristic that marks your diamond as being very individual and unique.