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The Four C's of Diamonds: Clarity

Diamond Four Cs Color

The Four C's Diamond Grading System

Clarity is one of the Four C's, representing the four variables that are used to calculate the quality and value of a diamond. The term "Clarity" refers to the presence or absence of tiny imperfections (inclusions) within the stone, and/or on the surface of the stone. As a consumer, it is important to learn and understand the clarity designations found within the "Four C's" diamond grading system.


All of the grades of diamond clarity shown in the table below, reflect the appearance of inclusions within the stone when viewed from above at 10x magnification Higher magnifications and viewing from other angles are also used during the grading process. In "colorless" diamonds, darker inclusions will tend to create the most significant drop in clarity grade. In fancy-colored diamonds, light or pale inclusions may show greater relief, making them more apparent, causing a greater drop in grade.

Diamond Clarity Designations

  • FL - "Flawless" no inclusions at 10 x magnification
  • IF - "Internally Flawless" no inclusions at 10 x mag. - small blemishes
  • VVS-1 - "Very Very Small" inclusions hard to see at 10 x magnification
  • VVS-2 - "Very Very Small" inclusions. VVS1 better than VVS2
  • VS-1 - "Very Small" inclusions visible at 10 x mag. - not naked eye
  • VS-2 - "Very Small" inclusions VS1 is better grade than VS2
  • SI-1 - "Small" or "Slight" Inclusions or "Imperfections" may be "eye clean"
  • SI-2 - "Small" or "Slight" Inclusions or "Imperfections" visible to naked eye
  • SI-3 - Inclusions large and obvious, little or no brilliance
  • I1 to I3 - Imperfect, with large Inclusions, fractures, and flaws

GIA Clarity Grading System

The chart below explains the GIA grading system for inclusions and imperfections. Considerations in grading the clarity of a diamond include the type of stone, point size and the location of inclusions. Inclusions that are near to, or break the surface, may weaken the diamond structurally, therefore reducing its value significantly. On the other hand, it may be possible to hide certain inclusions behind the setting of the diamond (depending on where the inclusion is located), thus minimizing any negative impact of the inclusion.

Diamond Clarity and Inclusion Diagram

Diamond Clarity Grade Inflation

A fairly common practice in the jewelry trade is grade-inflation or "grade bumping." According to the Federal Trade Commission's (FTC's) Jewelry Guides, a diamond must be within one clarity grade of its advertised amount at the time of sale. If a jeweler sells a diamond that has an actual grade of VS-1, he or she could legally sell it as a VVS-2.

Internal Diamond Inclusions

  • Carbon - Tiny black spots caused by undigested carbon inclusions (natts).
  • Clouds - Cloudy grouping of tiny pinpoints that may not resolve at 10X Magnification.
  • Feathers - Cleavage planes or internal fractures that have the appearance of feathers.
  • Grain Center - Concentrated area of crystal growth that appear light or dark.
  • Internal Graining - Irregular crystal growth causing internal distortions, waviness, haze.
  • Needles - Rutile-like needle inclusions.
  • Pinpoints - Minute crystals within the diamond that appear white.
  • Pique - Garnet or other Included gem stones
  • Twinning Wisps - Inclusions resulting from crystal twining during growth.

External Diamond Inclusions

  • Bearded Girdles - Fine cracks, chips, fringing, or feathers along the outer edge of girdle.
  • Bruising - A percussion mark caused by impact.
  • Cavities - An indentation resulting from a feather or damage during polishing.
  • Chips - Damage usually occurring on the sharp edge of a facet.
  • Knots - An inclusion that penetrates the surface, appearing as a raised area.
  • Indented Naturals - A natural indentation that was not removed by polishing.
  • Filled Fractures - Fractures that have been artificially filled.
  • Pits - Dislodged pinpoint inclusions at the surface.
  • Surface Graining - Visible surface lines caused by irregular crystallization during formation.

Diamond Fracture Filling

Diamond clarity is sometimes enhanced by filling fractures, much like repairing a crack in your car's windshield. Such diamonds are sometimes called "fracture filled diamonds". According to FTC guidelines, vendors should disclose this enhancement, and reputable filling companies will use filling agents which show an orange or pink flash of color.

There is a significant price discount for fracture-filled diamonds. The GIA will not grade fracture-filled diamonds, in part because the treatment isn't permanent. Reputable companies often provide for repeat treatments if heat causes damage to the filling. The heat generated by a blowtorch used to work on settings can cause damage, therefor it is essential to inform anyone working on a setting if the diamond is fracture-filled, so they can use greater care while working on the piece.

Laser Drilling

Laser drilling involves using a laser to burn a tunnel or hole to a carbon inclusion, followed by acid washing to remove the coloring agent. The drilling process leave tiny telltale shafts or tunnels that are visible under magnification.

The treatment is considered permanent and both the GIA and AGS will issue grades for laser drilled diamonds. The final clarity grade will be the grade that is assigned after treatment. According to Fred Cuellar in his book How to Buy a Diamond, "One out of every three diamonds sold in the United States is laser-drilled."

Human Caused Surface Blemishes

  • Abrasions - Whitish haziness along the junction of facets caused by wear.
  • Nicks - Small chips at facet junctions.
  • Scratches - Grinding Wheel Marks of scratches from contact with other diamonds.
  • Burn Marks - Surface burning from heat buildup during polishing.

"SI-3" is a grade sometimes used in the diamond industry. The designation of SI-3 was popularized by the EGL (European Gemological Laboratory) grading office. Neither the GIA nor the AGS (American Gemological Society), the most reputable well known US labs, assign this grade. Diamonds of this low grade would be inappropriate for jewelry.

On To:

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Diamond Enhancements & Treatments

Diamond Chemistry & Composition

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