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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. |
.
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.
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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!
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