Diamond Clarity Scale

Grading diamonds for clarity is the process for classifying the imperfections, both internal and external. Imperfections are called inclusions when internal and blemishes when external. The term clarity is preferred over purity because purity has a very narrow definition pure or impure. In order to accurately classify clarity in polished diamonds we need to have several levels of clarity. GIA has standardized a simple but detailed system.

FL-Flawless - These stones have no imperfections inside or on the outside of the stone under the magnification of a loupe of 10X magnification.

IF-Internally Flawless - This grade is awarded to diamonds with no internal flaws and only minor external blemishes. Nicks pits or girdle roughness, not on the table, which could be removed in re-polishing.

VVS1 , VVS2 - Very Very Slightly Imperfect - These stones have very, very small inclusions, which are extremely difficult to see under a loupe of 10X magnification.

VS1, VS2 - Very Slightly Imperfect - These stones have very small inclusions, which are slightly difficult to see under a loupe of 10X magnification.

SI1,SI2-Slightly Imperfect - These stones have inclusions, which are fairly easy to see under with a 10X magnification, and can be seen with the naked eye.

I1, I2, and I3-Imperfect - These stones have inclusions ranging from eye visible to very easily seen to the naked eye.

Flaws are caused by a shift in the pressure and or temperature during the time when the diamond is being formed. There are many types of imperfections, internal inclusions and external flaws.

Types of Internal flaws or Inclusions

Pinpoints - A small usually whitish dot that is difficult to see. There can be a number of pinpoints - cluster -or a cloud of pinpoints.

Dark Spot - A small crystal inclusion or thin flat inclusion that reflects the light like a mirror.

Colorless crystal - This is a small crystal of diamond, and sometimes-another mineral.

Cleavage - A small cleavage is a crack that has a flat plane, which if struck in a certain direction, could cause the diamond to split.

Feather - This is another name for crack. A feather is not dangerous if small and does not open through a facet.

Bearding or girdle fringes - Result from hastiness in the bruiting process when giving the diamond its initial shape in the cutting process.

Growth or grain lines - These can only be seen when rotating the diamond slowly during examination. They appear and disappear usually instantaneously and will appear in groups.

Knaat or twin lines - Slightly raised dot with a trail resembling a comet.

Laser treatment - A laser is used to make flaws less visible. A black spot can be vaporized and will disappear leaving a void in the diamond.

Types of External flaws or Blemishes

Natural - This usually occurs on the girdle and looks like a rough, unpolished area. A natural is a remnant of the original skin of the diamond. Indicates a shortage of rough or that the cutter made the largest acceptable diamond from the material he had to work with.

Nick - This is a small chip, usually on the girdle and can be caused by wear. Sometimes a nick or chip can be seen on the edge of a facet.

Girdle roughness - This blemish appears as crisscrossed lines, and can be removed by re-polishing.

Pitts or cavities - Pits or holes on the table facets.

Scratch - A scratch is usually a minor defect that can be removed by re-polishing.

Polishing lines - Many diamonds exhibit polishing lines and are the result of badly maintained polishing wheels.

Abraded or rough culets - The culet has been chipped or poorly finished.

The clarity grade can have a significant effect on the value of a diamond. The price variance between an Internally Flawless diamond and a Very Slightly Included One diamond clarity grade is significant at the wholesale level. The chart below illustrates the shift in pricing.

Grading Polished Diamonds For Color

When we speak of color in diamonds, most people think of the beautiful reds, blues, and yellows we see when a diamond flashes in the sun light. In fact grading a diamond for color means deciding by which amount the diamond's "body color" deviates from the whitest possible (water like colorless) color. Nature provides a continuous darkening in the tints from white to yellow, white to brown, and white to green. Divisions are determined by the ability of the human eye to separate one tint from an adjacent one that is slightly lighter or darker. This concept should not be confused with the sparkle, brilliance, or scintillation of the diamond.

Because of the diamond's high brilliance and dispersion of light, the color grade cannot be accurately determined by looking at the stone from the top (face up) position. It is best to observe color by examining the stone through the side of the pavilion (bottom of the stone) with the diamond upside down in a white paper grading trough. Please note in the illustration below the stone can be examined in several positions to obtain an accurate color grade.

GIA Gemological Institute of America pioneered the universal grading system in the early 1940's to supersede all confusing grading systems in use at that time. The GIA color grading classification starts from D, the finest color (colorless), and proceeds through the alphabet to z getting progressively more yellow. A set of master comparison stones calibrated to the exact color of every-other color: E, G, I ... is the most reliable method of grading diamonds for color. When compared in a standard viewing box or white folded paper the master stones are placed on either side of the diamond until the stones are sorted into the proper descending color values. This allow for the accurate color grading of the diamond.

The grades D, E, F are exceptionally fine white diamonds being the only grades referred to colorless. E color diamonds are extremely close to D color diamonds, however the color variance can only be detected in a controlled grading environment. The variance in price per carat between D and E color is significant at the wholesale level reflecting the rarity of the diamonds in the market.