Inclusions found in a diamond can be considered nature's birthmarks, the distinguishing characteristics that make each stone unique. When grading a diamond, the amount and type of inclusions has a direct impact on its clarity and value. Flawless diamonds containing no inclusions are extremely rare and very expensive. Diamonds in the Slightly Included to Very Slightly Included range (SI-VS) are often eye-clean and an excellent value. Always make sure that your diamond has been graded by a leading gemological institution such as the GIA or Gem Scan to avoid inflated clarity ratings (more about this in diamond certification).
A diamond's clarity rating is based on the size, number, and location of internal and external characteristics. Known as inclusions, internal characteristics include crystals, clouds, and feathers. External characteristics, or surface irregularities, are called blemishes. As most inclusions can't be seen by the naked eye, gemologists use a ten-power (10x) microscope to rate a diamond's clarity.
Flawless, Internally Flawless (FL & IF)
Contains no internal inclusions when viewed with 10x magnification. Internally Flawless diamonds may contain external characteristics (also known as blemishes).
Very Very Slightly Included (VVS1 & VVS2)
Contains minute inclusions that are extremely difficult to locate under 10x magnification.
Very Slightly Included (VS1 & VS2)
Contains minute inclusions, such as clouds, crystals, or feathers, which are difficult to locate with 10x magnification.
Slightly Included (SI1 & SI2)
Contains noticeable inclusions under 10x magnification, including clouds, knots, crystals, cavities, and feathers.
Included (I1 & I2)
Contains very obvious inclusions that can usually be seen with the naked eye, as well as under 10x magnification. Included diamonds sometimes display poor transparency and lack of brilliance.
Selecting a Clarity Grade
Below are some points to consider when selecting your desired clarity rating:
- Those who prefer a diamond with little or no inclusions will likely choose a clarity rating of FL-IF or VVS. Although they are priced higher, these high-quality diamonds boast a near-perfect appearance.
- While still considered high quality, diamonds rated in the VS clarity range will not cost as much as more premium clarities. VS diamonds will contain inclusions that are undetectable to the unaided eye
- Considered by many to be a great value, SI1-SI2 diamonds will contain inclusions that can be detected with magnification, yet are typically undetectable to the unaided eye and do not detract from the beauty of the diamond. If you are considering a diamond with an SI rating, it's crucial to examine the diamond in natural light with and without magnification.
- Those who desire large carat weights at lower prices often choose diamonds in the SI2-I1 clarity range. Inclusions in these stones are usually noticeable without magnification.
- The location of a diamond's inclusions significantly impacts the stone's clarity rating. External and internal characteristics hidden near the side facets of a diamond detract from its beauty less than inclusions and blemishes located in the center of the diamond.