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Roger Weller, geology instructor

Lisa C. Huff

Physical Geology

Fall 2006  

Diamond Inclusions 


         As a person who appreciates a beautiful diamond, I wanted to find out exactly what an inclusion was. Inclusions are normalities, not abnormalities in a diamond. They are useful in helping one identify a particular stone. Most inclusions do not affect the beauty of a diamond, and are called identifying characteristics because they provide a unique fingerprint. Most diamonds in rings have inclusions, but what is ok and what is not? Avoid the following flaws:

-Large milky or cloudy areas
-Big cracks...they threaten the durability. These include big feathers (big meaning 1/3 the diameter of the stone or more)
-Big chips...they will get bigger
-Big white, black or colored lines. They reduce brilliance and threaten durability

Note that inclusions are of two basic types, clear, whitish types and black carbon types, the second being more troubling to the clarity and brilliance of a diamond. Diamond Clarity is a measure of a diamond's internal flaws and impurities. A diamond that is virtually free of interior or exterior inclusions (commonly referred to as flaws) is of the highest quality, for nothing interferes with the passage of light through the diamond.

quartz EBSP

coesite EBSP










Extreme crustal oxygen isotope signatures preserved in coesite in diamond.

     The picture illustrates silica inclusions within diamond can readily be identified as monoclinic coesite (left) or trigonal quartz (right) by in situ, non-destructive point analyses.

     How clear is the stone? Clarity ranges from flawless (pure @ 10X) to I (included visible to the eye). Flawless: pure inside and out Internally Flawless: may have minor blemishes on the outside. VS1, VS2: have very small inclusions. VS1 inclusions are harder to see than VS2. SI1, SI2, SI3: have small inclusions I1, I2, I3: have inclusions visible to the naked eye. To determine a diamond's clarity, which is viewed under 10-x magnification by a trained gemologist? Small inclusions neither mar its beauty nor endanger its durability.

Chart of Clarity:

This chart illustrates the degree of clarity:

1.    Flawless - No internal or external flaws

2.    Internally Flawless - No internal flaws. Very rare and beautiful diamonds, which are quite expensive.

3.    VVS1, VVS2 - Very, Very Slightly Included Very difficult to see inclusions under 10-x magnification. An excellent quality diamond.

4.    VS1, VS2 - Very Slightly Included: Inclusions are not visible to the unaided eye. Less expensive than the VVS1 or VVS2 grade.

5.    SI3 - Slightly Included-EGL: SI3 is an EGL grade and is not recognized by GIA or other gemological institutions. It may be graded by GIA as either SI2 or I1. SI3 diamonds never have any black inclusions or cracks visible to the naked eye, but may have some very minor white inclusions, which can be seen with the naked eye.

6.    I1 - Included: an I1 clarity diamond will have a visible flaw, which can be seen with the naked eye, but there should only be one major flaw, which is not too obvious. If your budget only allows for an SI3 or I1 clarity diamond, be sure to examine it thoroughly before purchasing and make sure you cannot see any inclusions.

7.    I2, I3 - Included: These diamonds will have inclusions visible to the naked eye, and will have many black spots from the black inclusions and appear cloudy from the white inclusions, feathers and cracks.

     Now that there is more of an understanding about diamond inclusion, pictures courtesy of Jennifer Lewis, shows her diamond ring and the documents that make it authentic.










The diamond is a clarity of VS (1), meaning an excellent quality diamond.

The International Geology Institute gives a type of “birth certificate” for the diamond, describing the inclusions and a number of other characteristics.








































































Along with the “birth certificate” the International Gemological Institute issues a card for the registered owner giving the inclusions and other characteristics which makes this diamond unlike no other.  



Work Cited