A diamond purchase can be a stressful and scary process if you don’t know much about gemstones. You may hear and read unfamiliar terms when you begin shopping for a diamond. We want to help you feel at ease while shopping at State St. Jewelers so we’ve put together a short guide to help you shop like the pros.

When purchasing diamonds, our Graduate Gemologist from the Gemological Institute of America (GIA) carefully considers the cut, carat weight, color, and clarity of each stone to ensure that we provide the best quality diamonds. Each diamond is given a grade based on The Four C’s:


The Four C’s

A diamond’s cut may be the most important aspect of the stone and a beautiful cut requires the skill of a master cutter. To determine a cut grade, each diamond is evaluated based on its brilliance, fire, and sparkle.

  • Brilliance refers to the brightness of the diamond and is created by very precise cuts that allow light to enter the diamond and reflect in just the right way. If the cut is too deep or too shallow the light may exit at the bottom of the stone instead of reflecting and bouncing back out.
  • A diamond’s fire is the flash of colors that appear when the diamond is placed in direct light. Both the diamond’s natural color and an expert cut contribute to the perfect bending and dispersion of light.
  • The sparkle of a diamond is sometimes referred to as “scintillation.” This is achieved as the light bounces off each facet and moves toward the center of the diamond.


Carat Weight
Diamonds have been measured by carat weight since 1913 and it is important to remember this is a weight – not a size. Two diamonds of the same carat weight can actually vary in size depending on their cut and it is important to remember that a larger stone does not necessarily equal a better diamond.


You may be surprised to learn that diamonds come in a variety of colors. In fact, some of the most highly prized diamonds are blue, pink, or yellow.  These are often called ‘fancy’ colored diamonds. Truly colorless diamonds are very rare but when grading a white diamond, any hint of yellow will decrease the grade and price.


Almost all diamonds contain some form of internal or external imperfections. They could appear as black specks, small holes, or even a white cloud. We call these imperfections inclusions.  A clarity grade is based on the size, number, and placement of the inclusions as well as whether or not these inclusions alter the appearance of the diamond. GIA ranks diamonds based on characteristics visible with 10x magnification.

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