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Clarity
One of the Four C's for evaluating diamonds
by Gary Dutton

Clarity in diamond is a measure of the surface (blemishes) and internal (inclusions) characteristics of a polished diamond, and has, as does color, a major impact on value. Obviously, the fewer clarity characteristics a stone has, the more rare, and therefore valuable, it is. A diamond with the highest clarity grade is flawless (Fl), which means it has no discernable (at 10x) blemishes or inclusions, a situation not frequently encountered. Combine this with a D color in a diamond, and you would have a truly rare stone. However, this combination of highest color and clarity does not guarantee you a beautiful diamond. As we shall see below, it is most importantly the quality of the CUT (in combination with the other 3C's), which releases the beauty of the stone to the eye of the beholder(s).

Clarity characteristics are an inherent part of a diamond's life, and can arise from events which occurred during its formation deep in the earth, the mining procedures used to collect it, the cutting of rough into its final shape and the wearing of the stone. The descriptions of the more important characteristics of blemishes and inclusions are given below.

On most grading reports both blemishes and inclusions are plotted for the face-up and pavilion views of the stone. In general, blemishes are plotted in green, inclusions are plotted in red and extra facets and some naturals are plotted in black. Often, to avoid a messy looking plot, pinpoints, clouds and other minor details of clarity are not plotted, but indicated under "Comments:" at the bottom of the report.

Blemishes
Abrasions: tiny nicks on facet junctions or the culet; caused by wear or coming in contact with other diamonds.

Extra Facets: small facets placed to remove imperfections; not part of the cutting style. (Not to be confused with Added Facets which are added symmetrically and are part of the cutting style.)

Naturals: part of the original crystal surface remaining on the polished stone, frequently in the area of the girdle.

Polish Lines and Marks: tiny parallel lines or surface clouding left by irregular polishing or excessive heating during polishing, respectively.

Rough Girdle: a grainy or pitted girdle surface usually caused by poor workmanship.

Surface Graining: structural irregularities in crystal growth; may appear as faint lines, causing grooved or wavy surfaces and often cross facet junctions.

Inclusions
Bearding: tiny feathers extending inward from a bruted girdle surface. (Bruting is the process of rubbing two diamonds together to achieve the rounded shape of the diamond.)

Cavities and Chips: large/deep openings, and small/shallow openings in the diamond's surface, respectively.

Clouds: hazy or milky areas of many very small, usually crystalline inclusions.

Feathers: cleavages or fractures often white and feathery in appearance. (There are 4 cleavage planes in diamond, which run in octahedral directions. Fractures are breaks along planes other than cleavage planes and may alternate with them to form step-like feathers.)

Included Crystals: mineral crystals, such as garnet or peridot, contained inside a diamond.

Indented Naturals: natural rough surfaces that penetrate the stone and may distort the girdle outline.

Internal Graining: regions of irregular crystal growth that may appear as milky or colored lines or streaks, or may be reflective.

Laser Drill Holes: a tiny tube made by a laser; the surface opening may resemble a pit, while the tube usually resembles a needle.

Needles: needle-shaped included crystals.

Pinpoints: areas of minute, dot-like inclusions.

Twinning Wisps: cloudy areas produced by distorted crystal growth.

Grading Clarity
All clarity grading is performed at 10-times magnification using a hand loupe or gemological microscope under both artificial daylight and darkfield illumination conditions. Reflected light is used to detect and evaluate blemishes and darkfield light for inclusions. It's the face-up view that usually sets the clarity grade, however the face-up, pavilion and table-to-culet views are all taken into consideration during grading.

Clarity grades are largely determined by the collective visual appearance that a stone's inclusions exhibit in relationship to the size and shape of the stone. It is the consideration of the size, position, number, color/contrast and nature of these inclusions, which leads to the final clarity grade. Frequently, it is possible to quickly key on the most obvious inclusions seen in the face-up position in making a final grade determination. However, the higher clarity grades (Fl, IF, VVS1/2) are more difficult to distinguish than the lower (VS1/2, SI1/2, I1/2/3) because more care must be given to avoid overlooking small characteristics.

GIA Clarity Grading Scale
Clarity Grade Definition
Flawless (Fl) Free of all inclusions and blemishes.
Internally Flawless (IF) No inclusions and only minor blemishes visible at 10x magnification.
Very Very Slightly Included (VVS1) Minute inclusions extremely difficult to locate at 10x.
Very Very Slightly Included (VVS2) Minute inclusions extremely difficult to locate at 10x.
Very Slightly Included (VS1) Minor inclusions difficult to locate at 10x.
Very Slightly Included (VS2) Minor inclusions somewhat easy to locate at 10x.
Slightly Included (SI1) Noticeable inclusions easy to locate at 10x.
Slightly Included (Sl2) Noticeable inclusions very easy to locate at 10x
Imperfect (I1) Obvious inclusions usually easy to locate with the unaided eye.
Imperfect (I2) Obvious inclusions easy to locate with the unaided eye.
Imperfect (I3) Obvious inclusions very easy to locate with the unaided eye and which may threaten stone's durability.

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Below is a chart for comparing the clarity grading scale of GIA with that of AGS, which is a numerical scale ranging from 0 to 10. Accompanying each major clarity category is an approximate diagrammatic representation of how the inclusions might appear under 10x magnification. This serves only to give you an idea of the relative difference in clarity characteristics between categories.

Effect of clarity on price: Roughly for a 1-1.5ct. D color round brilliant diamond, going from IF to VVS1 clarity will result in about a 25% decrease in price, and a further 10% decrease for each clarity grade (VVS2=-35%, VS1=-45%, VS2=-55%) until SI1 and SI2 where 5% further decreases are in order (SI1=-60%, SI2=-65%). Again as with color, the greatest saving is in the first step down.

Effect of both color and clarity on price: Again using a D, IF, 1-1.5ct. round diamond as the standard, going one grade lower in both color and clarity for each step drops the price about 40% for a E, VVS1; ~50% for a F, VVS2; ~60% for a G, VS1; ~70% for a H, VS2 and ~75% for a I, SI1.

Please keep in mind that these numbers are only rough estimates, and are not meant to be used as a pricing guide.

Dutton's Diamonds does not sell diamonds with imperfect (I1/2/3) clarity grades. We sell only those diamonds with SI clarity grades and above.

 

The SI3 Clarity Grade - The SI3 clarity grade has evolved to mean a mostly "eye clean" I1 clarity, in other words a designation for a low SI2 or high I1 clarity. The purpose for trying to establish such a grade is to avoid the marked price drop from SI2 to I1 and to make these stones more appealing to the customer. The European Gemological Lab. (EGL) in Los Angeles and New York use this grade on their reports, as do some trade organizations (Rapaport Diamond Report), dealers and jewelers. (You can read a discussion of why this clarity grade is not needed in Jewelers' Circular Keystone (JCK), June, 2000, pp. 226-228.)

Neither GIA nor AGS recognize the SI3 clarity grade. Dutton's Diamonds adheres to the established GIA clarity grading scale and does not sell diamonds with the SI3 clarity grade.

Clarity enhancements are performed by bleaching dark inclusions following laser drilling, or where inclusions reach the stone's surface (and this can include the above case) they can be filled with a liquid agent which hardens with the same refractive index as diamond, thus rendering the inclusion largely invisible. If the original inclusion compromises the stone's durability, subsequent shock to the stone could enlarge the inclusion, thus making it visible. Alternatively, the filler may deteriorate for any number of reasons, changing the clarity appearance of the stone. GIA will grade diamonds which have laser drill holes with an appropriate note on the report, but will not grade those stones which have had fracture filled, clarity enhanced procedures applied. Fortunately, the material used to fill fractures is quite easily detected.

Dutton's Diamonds does not deal in or sell diamonds which have been laser drilled or clarity enhanced in any way!

Color    Clarity   Carat Weight   Cut

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