Diamond clarity

Diamond clarity is the quality of diamonds that relates to the existence and visual appearance of internal characteristics of a diamond called inclusions, and surface defects, called blemishes. Clarity is one of the four Cs of diamond grading, the others being carat, color, and cut.

Inclusions are solids, liquids, or gases that were trapped in a mineral as it formed. They may be crystals of a foreign material or even another diamond crystal, or may have produced structural imperfections, such as tiny cracks that make a diamond appear whitish or cloudy. The number, size, color, relative location, orientation, and visibility of inclusions can all affect the relative clarity of a diamond. A clarity grade is assigned based on the overall appearance of the stone under ten times magnification, which is the standard magnification for loupes used in the gem world.

Most inclusions present in gem-quality diamonds do not affect the diamonds' performance or structural integrity and are not visible to the naked eyes. However, large clouds can affect a diamond's ability to transmit and scatter light. Large cracks close to or breaking the surface may reduce a diamond's resistance to fracture.

Diamonds with higher clarity grades are more valued, with the exceedingly rare "Flawless" graded diamond fetching the highest price. Minor inclusions or blemishes are useful, as they can be used as unique identifying marks analogous to fingerprints. In addition, 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.

Heavily included diamonds used to be solely for industrial use. In recent years, salt and pepper diamonds have gained increasing popularity.

Inclusions and blemishes

There are several types of inclusions and blemishes, which affect a diamond's clarity to varying degrees. Features resulting from diamond enhancement procedures, such as laser lines, are also considered inclusions or blemishes.

Inclusions

• Clouds
• Feathers
• Included crystals or minerals
• Knots
• Cavities
• Cleavage
• Bearding
• Internal graining
• Pinpoint
• Laser lines
• Twinning Wisp
• Grain center
• Laser drill hole
• Knot
• Needle

Blemishes

• Polish lines
• Grain boundaries
• Naturals
• Scratches
• Nicks
• Pits
• Chips
• Breaks
• Dark spots
• Light spots
• Abrasions

Clarity grading

Gemological Institute of America grading system

History

In 1952, Richard T. Liddicoat, along with Marquis Person, Joe Phillips, Robert Crowningshield and Bert Krashes began to work on a new diamond grading system which they called the "diamond grading and evaluation appraisal". The clarity categories and grades are:

• Flawless category (FL) diamonds have no inclusions or blemishes visible under 10× magnification.

Grading systems by other organizations

The clarity grading system developed by the GIA has been used throughout the industry as well as by other diamond grading agencies including the American Gemological Society (AGS), and the International Gemological Institute (IGI). There are other smaller labs which use the GIA system as well. These grading agencies base their clarity grades on the characteristics of inclusions visible to a trained professional when a diamond is viewed from above under 10× magnification.

World Jewellery Confederation

{| class="wikitable" style="margin:auto; width:90%; table-layout:fixed; text-align:center;"

|+CIBJO diamond clarity grading scale

| colspan="4" style="border-right: 2px solid black" | GIA

| colspan="4" style="border-right: 2px solid black" | all stones

| colspan="2" style="border-right: 2px solid black" | FL

| colspan="2" style="border-right: 2px solid black" | IF

| colspan="3" | VVS₁

| colspan="3" style="border-right: 2px solid black" | VVS₂

| colspan="3" | VS₁

| colspan="3" style="border-right: 2px solid black" | VS₂

| colspan="5" | SI₁

| colspan="5" style="border-right: 2px solid black" | SI₂

| colspan="4" | I₁

| colspan="4" | I₂

| colspan="4" style="border-right: 2px solid black" | I₃

|-

| colspan="4" style="border-right: 2px solid black" | CIBJO

| colspan="4" style="border-right: 2px solid black" | over 0.47ct

| colspan="4" style="border-right: 2px solid black" | Loupe clean

| colspan="3" | VVS₁

| colspan="3" style="border-right: 2px solid black" | VVS₂

| colspan="3" | VS₁

| colspan="3" style="border-right: 2px solid black" | VS₂

| colspan="5" | SI₁

| colspan="5" style="border-right: 2px solid black" | SI₂

| colspan="4" | P_I

| colspan="4" | P_II

| colspan="4" style="border-right: 2px solid black" | P_III

|-

| colspan="4" style="border-right: 2px solid black" | CIBJO

| colspan="4" style="border-right: 2px solid black" | under 0.47ct

| colspan="4" style="border-right: 2px solid black" | Loupe clean

| colspan="6" style="border-right: 2px solid black" | VVS

| colspan="6" style="border-right: 2px solid black" | VS

| colspan="10" style="border-right: 2px solid black" | SI

| colspan="4" | P_I

| colspan="4" | P_II

| colspan="4" style="border-right: 2px solid black" | P_III

|}

The World Jewellery Confederation developed the International Clarity Scale for grading diamonds. This clarity scale mirrors the GIA grading scale, except nomenclature varies. The system names these clarity grades; Loupe Clean, Very, very small inclusions (VVS1 and VVS2), Very small inclusions (VS1 and VS2), Small inclusions (SI1 and SI2), Piqué (P1, P2, and P3; from a French word meaning "blemished").

Clarity grading by WJC standards is by examination using a 10× achromatic, aplanatic loupe in normal light.

International Diamond Council

{| class="wikitable" style="margin:auto; width:101%; table-layout:fixed; text-align:center;"

|+IDC diamond clarity grading scale

| colspan="4" style="border-right: 3px solid blue" | GIA

| colspan="4" style="border-right: 3px solid blue" | FL

| colspan="4" style="border-right: 3px solid blue" | IF

| colspan="4" | VVS₁

| colspan="4" style="border-right: 3px solid blue" | VVS₂

| colspan="4" | VS₁

| colspan="4" style="border-right: 3px solid blue" | VS₂

| colspan="4" | SI₁

| colspan="4" style="border-right: 3px solid blue" | SI₂

| colspan="4" | I₁

| colspan="4" | I₂

| colspan="4" style="border-right: 3px solid blue" | I₃

|-

| colspan="4" style="border-right: 3px solid blue" | IDC

| colspan="4" style="border-right: 3px solid blue" | Loupe clean

| colspan="4" style="border-right: 3px solid blue" | Loupe clean

| colspan="4" | VVS₁

| colspan="4" style="border-right: 3px solid blue" | VVS₂

| colspan="4" | VS₁

| colspan="4" style="border-right: 3px solid blue" | VS₂

| colspan="4" | SI₁

| colspan="4" style="border-right: 3px solid blue" | SI₂

| colspan="4" | P_I

| colspan="4" | P_II

| colspan="4" style="border-right: 3px solid blue" | P_III

|}

The IDC or the International Diamond Council uses a very similar standard to CIBJO. IDC loupe clean stones that have external blemishes have notations made on the grading report. IDC clarity grading is by examination using a 10× achromatic, aplanatic loupe in normal light.

| colspan="4" style="border-right: 2px solid black" | IF

| colspan="3" | VVS₁

| colspan="3" style="border-right: 2px solid black" | VVS₂

| colspan="3" | VS₁

| colspan="3" style="border-right: 2px solid black" | VS₂

| colspan="4" | SI₁

| colspan="4" | SI₂

| colspan="4" style="border-right: 2px solid black" | SI₃

| colspan="3" | I₁

| colspan="4" | I₂

| colspan="4" style="border-right: 2px solid black" | I₃

|-

| colspan="4" style="border-right: 2px solid black" | EGL India

| colspan="2" style="border-right: 2px solid black" | FL

| colspan="2" style="border-right: 2px solid black" | IF

| colspan="3" | VVS₁

| colspan="3" style="border-right: 2px solid black" | VVS₂

| colspan="3" | VS₁

| colspan="3" style="border-right: 2px solid black" | VS₂

| colspan="4" | SI₁

| colspan="4" | SI₂

| colspan="4" style="border-right: 2px solid black" | SI₃

| colspan="3" | P₁

| colspan="4" | P₂

| colspan="4" style="border-right: 2px solid black" | P₃

|}

The European Gemological Laboratory (EGL) introduced the SI3 as a clarity grade. While intended as a range to include borderline SI2 / I1 stones, it is now commonly used to mean I1's which are nearly "eye clean", that is, which have inclusions which are not obviously visible to the naked eye. Because GIA and EGL use the same nomenclature, but apply the standards differently, purchasers of diamonds can be easily confused or mislead.

Clarity grading considerations

All grades reflect the appearance to an experienced grader when viewed from above at 10× magnification, though higher magnifications and viewing from other angles are used during the grading process. The grader studies the diamond for internal characteristics and judges them on the basis of five clarity factors: size, number, position, nature, and color or relief. The clarity grade is assessed on the basis of the most noticeable inclusions, the so-called "grade setting inclusions". Less significant inclusions are ignored for the purposes of setting the grade; however, they may still be plotted onto a diamond plot chart.

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.

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". Reputable vendors must disclose this filling and reputable filling companies use filling agents which show a flash of color, commonly orange or pink, when viewed closely. There is a significant price discount for fracture-filled diamonds. The GIA will not grade fracture-filled diamonds, in part because the treatment is not as permanent as the diamond itself. 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.

GIA, as a matter of policy, does not grade clarity-enhanced diamonds but it will grade laser-drilled diamonds since it considers the enhancement to be permanent in nature. If a GIA report has the words "clarity enhanced" or "fracture filled", it is surely a counterfeit report.

See also

• Diamond
• Diamond color
• Diamond cut
• Diamond enhancement
• Gemology
• List of diamonds
• Synthetic diamond

References