Grading of Lab Created Diamonds

Are you curious how lab created diamonds are graded? How do you know if  you are purchasing a valuable (lab created) diamond?  The answer is quite simple.  The grading of a lab created diamond is equal to that of a naturally mined diamond.  The value is determined by the stone’s 4 C’s - Carat, Cut, Color and Clarity!  We will review what each of these mean in more detail below. 

The 4 C's of a diamond were established by the Gemological Institute of America or GIA and they have become a standardized grading system used by trained jewelers and gemologists today.   The 4 C’s determine the diamond's quality which will in turn determine the overall cost of the diamond to the consumer. *To learn more about the GIA’s development of the diamond’s 4 C’s please visit the GIA site HERE 

Purchasing a diamond, whether naturally or lab grown, can be quite overwhelming to the novice consumer.  Once you have a clearer understanding of the 4 C's and how diamonds are graded, you’ll find that it is much easier to navigate and determine if a diamond is actually worth it’s price tag.

1. Carat- A diamond’s size can be measured in two ways- the stone’s Carat Weight and/or the stone’s Millimeter (MM) size. A diamond’s carat weight is equal to the stone’s overall weight on a diamond scale, which is how a diamond’s size is actually measured.  Essentially the larger the carat size the higher the value of the diamond. Carat is the most obvious and visible of the 4 C’s.   However, size is not the only determination of the diamond’s value.   A diamond with a larger carat weight could have poorer Clarity and Color, therefore lowering the stone’s value compared to a smaller diamond with better clarity and color.   You will also find that a diamond’s size is displayed in (MM) millimeters. This is the actual diameter of the diamond and is another important factor when determining your preferred stone size.  To simplify the process each diamond cut, whether round or square, will have a MM size that equates to the stone’s carat weight.  You can use the chart below to approximate the size range of the stone within the  setting you plan to mount it into. 

 

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2. Cut: Don’t confuse a diamond’s cut with the diamond’s shape.  These terms are used interchangeably but in regard’s to the 4 C’s the cut is based upon the ability of the diamond  to refract light.  The ideal cut will maximize the brilliance of the stone. Jewelers determine a diamond’s cut grade based upon how the light hits the stone and is then refracted-maximizing brilliance.  When light is upon a diamond it should ultimately return the light from the stone to your eye. The cut of the diamond will directly impact the amount of refraction, which ultimately impacts the value of the stone.  Each shape of a diamond has a specific ideal cut that will include a certain number of angles and facets which will determine the diamond’s overall brilliance.    

A diamond’s cut has four grading categories that jewelers and gemologists will assign to the diamond when determining the diamond’s overall value.  This scale was created for naturally mined diamonds but it is also used today to determine the cut grade and the value of a lab created diamond. 

  • Excellent (EX) - Diamonds with an Excellent cut grade precisely cut to unleash the maximum amount of fire and ice.  With an excellent diamond cut there is little to no light leakage when light passes through a diamond.  This cut is rare as it is only found in approximately 3% of all naturally mined diamonds in the world.  An “excellent cut” diamond will of course carry the highest cost and value. 
  • Very Good (VG) - A “Very Good” cut diamond will be able to capture a majority of light. This cut provides a high amount of brilliance, fire and ice.  A Very Good grade is the preferred cut for most diamonds.  This cut could also improve other poorer characteristics of a diamond including the stone’s color or clarity.  The top 15% of all naturally mined diamonds fall under this rating and carry a very high value. 
  • Good (G) -  A diamond with a “Good” cut may have some light that leaks through, but overall these stones will shine bright. Diamond cutters may intentionally seek to obtain a “Good Cut” for a specific style or shape of stone.  This stone cut is a bit more budget friendly as it will combine quality of cut with the size of the stone. The top 25% of all natural diamonds have a “Good Cut” grade.
  • Fair & Poor (FP) - A diamond with a “Fair to Poor Cut” grade  will loose a significant amount of light due to either being cut too deep or too shallow. These diamonds will have little brilliance, fire and ice.  The “Fair to Poor Cut” diamond will not meet the stringent diamond characteristics to be considered a diamond with clarity.  This cut is found in approximately 35% of all naturally mined diamonds and jewelers/gemologists are required to identify a diamond’s cut grade. 
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Illustration A- This illustration demonstrates how the quality of a round diamond's cut can impact the amount of light refraction, increasing the stone’s sparkle, fire, and ice!

A diamond’s cut has four grading categories that jewelers and gemologists will assign to the diamond when determining the diamond’s overall value.  This scale was created for naturally mined diamonds but it is also used today to determine the cut grade and the value of a lab created diamond. 

  • Excellent (EX) - Diamonds with an Excellent cut grade precisely cut to unleash the maximum amount of fire and ice.  With an excellent diamond cut there is little to no light leakage when light passes through a diamond.  This cut is rare as it is only found in approximately 3% of all naturally mined diamonds in the world.  An “excellent cut” diamond will of course carry the highest cost and value. 
  • Very Good (VG) - A “Very Good” cut diamond will be able to capture a majority of light. This cut provides a high amount of brilliance, fire and ice.  A Very Good grade is the preferred cut for most diamonds.  This cut could also improve other poorer characteristics of a diamond including the stone’s color or clarity.  The top 15% of all naturally mined diamonds fall under this rating and carry a very high value. 
  • Good (G) -  A diamond with a “Good” cut may have some light that leaks through, but overall these stones will shine bright. Diamond cutters may intentionally seek to obtain a “Good Cut” for a specific style or shape of stone.  This stone cut is a bit more budget friendly as it will combine quality of cut with the size of the stone. The top 25% of all natural diamonds have a “Good Cut” grade.
  • Fair & Poor (FP) - A diamond with a “Fair to Poor Cut” grade  will loose a significant amount of light due to either being cut too deep or too shallow. These diamonds will have little brilliance, fire and ice.  The “Fair to Poor Cut” diamond will not meet the stringent diamond characteristics to be considered a diamond with clarity.  This cut is found in approximately 35% of all naturally mined diamonds and jewelers/gemologists are required to identify a diamond’s cut grade. 

3. Color:  Any diamond can range in color from bright white to a soft tint of of yellow/brown. The GIA has assigned a letter system to the diamond color from D (brightest white) to Z (brownish color).  Color, like cut and clarity will impact the amount of fire and ice the diamond may reflect.  A diamond with a more yellow/brown tint will seem to have less brilliance.  In order to determine a diamond’s color, the stone must be placed face down, on a white background and evaluated against the diamond color scale as seen below. The D-F colorless diamonds will carry the highest value and cost.  Any diamond with a color rating from J to R begins to lose value and is lower in cost.  The process of created a Lab created diamond allows for higher controls over the color that is created during the manufacturing process.  Yes a lab created diamond can be manufactured to be a colored stone including; yellow, pink or blue,  However, the majority of white lab diamonds will rank higher in color from a color rating of D-G.  There are very few lab created diamonds that have a yellow hue unless it was purposefully designed by the manufacturer to be  this color. 

 

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4. Clarity- Clarity is determined by the number of natural imperfections found within the diamond.  Naturally mined diamonds will develop microscopic imperfections during  the stone’s formation.  These imperfections are also called the diamond’s  “inclusions”  and will have direct impact on the diamond’s overall value and cost. 

All naturally mined diamonds will have inclusions, but some poorer graded diamonds will have many more inclusions than highly graded diamonds.  The amount of inclusions within a diamond will impact the clarity of the diamond and the stone’s ability to refract light.  These imperfections will impact the diamond’s overall brilliance, increasing or decreasing it’s value and cost. 

In order to determine the number of inclusions within a diamond it must be magnified at 10 times its size, and examined by a well trained eye.  When shopping for a diamond you will see that jewelers assign a rating to the stone’s Clarity which will range on a scale from “FL - I3"   An “FL” or a “IF” graded diamond is rarely found in naturally mined diamonds and carry the highest value.  The most common clarity rating found in a majority of retail jewelry establishments or within diamond distributers will range from VVS1 to VS2.    

 

 

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Grading Lab Created Diamonds

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