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Clarity of Diamonds

Clarity of Diamonds

Only in 1953 the GIA started to grade clarity & color in the grading scales we use today.

The clarity grade of a diamond is determined by its clarity inclusions that divide into three:

  1. Internal Characteristics (inclusions)

These inclusions badly affect the clarity because:

  1. It is difficult to repair them – repairing them substantially reduces the diamond’s weight.
  2. They are usually bright and thick, and therefore they look worse in the loupe.

 

  1. External Characteristics (Imperfections)

External imperfections affect the clarity grade of a diamond less severely because:

  1. It is easy to repair them – repairing them does NOT substantially reduce the diamond’s weight.
  2. They have no brilliance and no thickness, and therefore they are not immediately visible in the loupe.

 

  1. Integrated Inclusions – Internal and External Characteristics

 

The internal inclusions are:

  1. Crystal (bubble) – A mineral crystal contained in a diamond. Usually in a round or ellipse shape.

*Black Pique – A black inclusion in the stone, usually the inclusion is black because of graphite concentration. In the Diamond industry it is common to define most of the internal inclusions by the name: “Piquesim”.

  1. Needle – A thin, elongated crystal that looks like a tiny rod at 10X.
  2. Cleavage – A linear crack in the stone.
  3. Feather – General trade term for a break in a gemstone, often white and feathery in appearance.
  4. Bearding –Very small feathers that extend from the girdle surface into the stone; can result from the cutting process.
  5. Pinpoint – A very small crystal that looks like a tiny dot at 10X. If this is the only inclusion in the stone, it will have a high clarity grade, usually Vvs1 or Vvs2.
  6. Cloud – Many tightly grouped pinpoints that might be too small to distinguish individually but together have a hazy appearance.
  7. 8. Milky Stone – Sometimes a stone has a huge cloud inside it, and this causes the stone to look lifeless and pale – milky appearance. Usually you can see it with the loupe. If the stone is extremely cloudy you can see it with the naked eye.

When the GIA write a comment in the comments section: “Clarity grade is based on clouds that are not shown” it means that there are clouds in the stone, but they are not plotted in the certificate. Sometimes this comment indicates that this is a milky stone.

  1. Twinning wisp – A series of pinpoints, clouds, or crystals.
  2. Chip – A shallow opening caused by damage to the stone’s surface that typically occurs at a girdle edge, facet junction, or culet.
  3. Bruise –A tiny area of impact accompanied by very small, root-link feathers; typically occurs at a facet junction.
  4. Laser Drill Hole – An artificial inclusion in the stone. A laser is used to drill a hole in the diamond in order to inject chemicals designed to whiten black inclusions. In order to hide the drill hole, this treatment is performed at a 90-degree angle to the table. The laser treatment is plotted in the certificate as one of the key to symbols: Laser drill hole.
  5. KM – Laser drilling within a diamond that creates a surface-reaching feather, or expands a pre-existing feather around a dark inclusion so that it reaches the surface. The feather then provides access for bleaching to decrease the visibility of the inclusion. After the treatment the only evidence of treatment are a cleavage and a white inclusion. Since these features can naturally occur in a diamond, it is very difficult to determine that the stone was treated. This treatment can usually only be identified by a gemological institute. The GIA does not plot the KM in the certificate, but writes down a comment: Internal Laser Drilling is not shown.
  6. Internal Graining Lines – Lines, angles, or curves that might appear whitish, colored, or reflective, or affect transparency at 10X; caused by irregularities in crystal growth.

 

The external characteristics. Reduce the clarity grade to: I.F

  1. Natural – A portion of the original surface of a rough diamond left on a fashioned stone; usually on or near the girdle.Naturals are usually not removed in order to conserve weight. It can affect the clarity grade to: I.F. Also, it affects the symmetry grade of the stone if the natural is located in the crown, or is seen through the crown.
  2. Scratch – A thin, dull, white line across the diamond’s surface. It also affects the polish grade of the stone.
  3. Extra facet – A facet that’s not required by the cutting style, placed without regard for the diamond’s symmetry; most often found near the girdle. Used to cover minor external imperfections such as a natural, a scratch, or a chip. An extra facet affects the clarity grade to I.F. It also affects the symmetry of the stone.
  4. Surface Graining Lines – Results from irregularities in crystal structure.
  5. Other polish imperfections like Burnt marks, Polish lines, Abrasions, Nick, Pit.

 

The integrated inclusions are:

  1. Indented natural – A portion of the rough diamond’s original surface that dips below a polished diamond’s surface.
  2. 2. Cavity – An angular opening created when part of a feather breaks away or when a surface-reaching crystal drops out or is forced out during polishing.
  3. Etch Channel – An inclusion that looks like a pipe in the stone. It is a very rare inclusion.
  4. Knot -White or transparent diamond crystal that extends to the surface after fashioning. The sawing and cutting directions of the knot are different from those of the larger diamond. Therefore, the knot interrupts the sawing and cutting processes and it might affect the polish of the stone.

 

 

Clarity Grades

1.FL (Flawless) – A stone which is completely clean and has no internal or external characteristics.

  1. IF (Internally Flawless) – A stone which has no internal inclusions, but can have minor external imperfections such as a tiny natural, a tiny scratch, an extra facet, or surface graining lines.
  2. VVS1, VVS2 (Very Very Slightly included) – Stones which have very very small internal inclusions, such as pinpoints, clouds, needles and tiny cleavages.
  3. VS1, VS2 (Very Slightly included) – Stones which have small internal inclusions.
  4. SI1, SI2 (Slightly Included) – Stones which have medium-sized internal inclusions.

*SI3 (Slightly included) – this clarity grade appears in the Rapaport list but is not recognized by the G.I.A and the H.R.D

  1. I1 (P1), I2 (P2), I3 (P3) (Included) – Stones which have large or very large internal inclusions that are seen with the naked eye.

How to decide what the clarity grade is by loupe and by microscope?

  1. If an inclusion is not seen under 10x magnification (by the Loupe) or by the microscope, it will be ignored and will not affect the clarity grade.
  2. F external imperfections can usually be seen only by microscope under 10 x magnifications. Even though a natural can be seen by the Loupe.
  3. VVS1 internal inclusions and most VVS2 internal inclusions can be seen only by the microscope under 10 x magnifications. The difference between VVS1 and VVS2 is that VVS1 internal inclusions can be seen only from the pavilion under 10x magnification and VVS2 internal inclusions can be seen from the pavilion as well as from the crown under 10 x magnifications in microscope and sometimes with the Loupe.
  4. VS1 internal inclusions are seen with much difficulty by the Loupe.
  5. VS2 internal inclusions are seen with little difficulty by the Loupe.
  6. SI1 internal inclusions are seen quite easily by the Loupe.
  7. SI2 internal inclusions are seen very easily by the Loupe.
  8. I1, I2, and I3 internal inclusions are seen with the naked eye (without the Loup).
  9. SI3 inclusions are inclusions whose size fit I1 but are seen mainly with the Loupe and hardly with the naked eye.

Five criterions to determine the clarity grade

  1. The size of the inclusion
  2. The position of the inclusion
  3. The amount of the inclusions
  4. The kind of the inclusion – internal or external.
  5. The color and appearance of the inclusions.

Plotting clarity inclusions in a gemological certificate

  1. Internal inclusions are marked in red.
  2. External imperfections are marked in green.
  3. Extra facets are marked in black.
  4. Combined inclusions such as a cavity, or indented natural will be marked where they are in both green and red.
  5. Internal inclusions which are seen from the crown will be marked in the crown in red.
  6. External imperfections will be marked where they are in green.
  7. An open cleavage that touches the surface of the stone will be marked where it is in red.
  8. An inclusion should be marked only once even if it reflects several times.
  • If the GIA believes that there is a possibility to upgrade the clarity grade of the stone in terms of the weight of the diamond, it will issue a “sleeve” for the stone. In the sleeve, the inclusions that should be fixed are marked. Usually it will be minor inclusions that can be easily fixed.
  • If in the clarity grade it is written: VS1 Potential or VVS2 Potential or VVS1 Potential, it means that the stone is potential to an IF clarity grade.
  • If in the clarity grade it is written: VS1 Improvable or VVS2 Improvable, it means that the clarity grade of the stone can be improved to VVS2 or VVS1