Grading Diamonds

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Have you ever wondered how to know if you’re buying a nice quality diamond?  It can be a bit overwhelming, but with a little education of a diamond’s quality characteristics it can be simple.  Every diamond is unique as a snowflake, no two are alike.

There was no agreed upon way to grade diamonds until the middle of the twentieth century.  GIA, which stands for Gemology institute of America, created the first and now globally accepted standard for grading diamonds.  They are called the 4 C’s:  Color, Clarity, Cut and Carat weight.  When you know these four things, you can determine the quality of a diamond from anywhere in the world.

This is very important because the 4C’s became a universal language that enabled customers to know exactly what they were purchasing.

Let’s look at color first.  Actually diamond color means lack of color, so the grading of color is based on the absence of color instead of the presence of color.  The perfect color would be colorless, consequentially it costs more.  The color grading system developed by GIA goes from D to Z, measuring the degree of color, D being the best, representing colorless.

Many of these color grades are so subtle that they can’t be seen with the untrained eye, but make a big difference in the diamond quality and price.

Fancy colored diamonds are not graded on the D-Z scale.  They are extremely rare natural phenomenon of nature.  These diamonds, while deep in the earth, are exposed to certain trace elements, the result can be a fancy colored diamond in almost any color of the rainbow, yellow, pink, orange, red, blue and green.  As with anything so rare these diamonds come with a premium cost.

Color Chart
Color Chart

The second C is clarity and refers to the absence of inclusions and blemishes.  Natural diamonds are the result of carbon that has been exposed to extreme heat and pressure deep in the earth.  This process results in different characteristics that make each one unique.  What causes inclusions is small crystals can become trapped in the diamond when it is forming.  While no diamond is perfect, the closer it comes, the higher its value is.

  • Flawless (FL): Flawless diamonds show no inclusions or blemishes of any sort under 10X magnification when observed by an experienced grader.
  • Internally Flawless (IF): Internally Flawless diamonds have no inclusions when examined by an experienced grader using 10X magnification, but will have some minor blemishes.
  • Very Very Slightly Included (VVS1 & VVS2): Very very slightly included diamonds contain minute inclusions that are difficult even for experienced graders to see under 10X magnification.
  • Very Slightly Included (VS1 & VS2): Very slightly included diamonds Contain minute inclusions such as small crystals, clouds, or feathers when observed with effort under 10X magnification.
  • Slightly Included (SI1 & SI2): Slightly included diamonds Contain inclusions (clouds, included crystals, knots, cavities, and feathers) that are noticeable to an experienced grader under 10X magnification.
  • Included (I1 & I2): Included diamonds Contain inclusions (possibly large feathers or large included crystals) that are obvious under 10X magnification and may affect transparency and brilliance.

The third C is cut, possibly the most important of the 4 C’s.  The cut of the diamond unleashes the light.  We sometimes think of the diamonds cut as its shape, (round, oval, princess) but when grading a diamond it is really about how well the diamond facets interact with light.  So its proportions, symmetry, and polish all can deliver the most sparkle if cut properly.  The cut can determine if the diamond will be appealing to the eye.

To determine a diamonds cut grade an optical measuring device creates a three-dimensional model to determine the diamonds proportions and angles.  It is possible to trace light reaction and measure its brilliance with sophisticated computer modeling.

When thinking about a diamonds actually shape (round, oval, princess) that is a total personal choice as to what you like and desire.  Round is the most common but all diamond shapes are beautiful in their own right. When you pick a diamond the main thing to ask yourself is:  Does it look beautiful to you?

4Cs Cut Angles
4Cs Cut Angles

The last C is carat weight, which is the measurement of how much a diamond weighs.  A metric “carat” is defined as 200 milligrams.

There are 100 points to a 1.00 carat.  ( 50 points to a ½ carat) This enables precise measurements to the hundredth decimal place.

All else being equal, diamond prices increases with diamond carat weight, because larger diamonds are rare and more desirable.  However, two diamonds of the same weight can have very different values depending on the other C’s.

Remember that a diamonds value is determined by using all the C’s not just carat weight.

Some weights are considered “magic sizes” half carat, three quarter carat, and carat.  Visually there is not much difference between a .99 ct. and a 1.00 ct., but the price difference between the two can be a lot.

Stones can come with a diamond report.  What that means is an outside source grades the diamond and gives a report on their findings.  GIA (Gemological Institute of America) is among the most respected organizations in the diamond industry, but there are others that can also do reports.  The report will give a detail description of the 4 C’s.

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