Buying a diamond can be a confusing process and understanding the diamond rating system will make all the difference. Most people don’t quite know where to start or what they want. Luckily that is where the 4C’s come in! The 4C’s are a diamond education system by GIA, The Gemological Institute of America, to serve as a scale for global diamond standards. The 4C’s are color, clarity, cut and carat weight.


The ideal and highest rated diamond is completely absent of color. The rating scale goes from D to Z, with D being colorless and Z containing the most color. Although these differences in color will seem almost unnoticeable, they make a huge difference in overall quality and price.


Clarity describes whether or not the diamond has imperfections of any kind such as “blemishes” or “inclusions.”

  • Inclusions are internal imperfections such as crystallizations visible through the surface of the diamonds.
  • Blemishes are external issues with thediamond such as a surface scratch.


The clarity scale ranges from the highest grade of “flawless,” a diamond with no blemishes or inclusions, to “included,” where the imperfections can be easily found.


Most people believe that a diamond’s cut is its shape – oval, square, round etc. However, cut actually refers to the interaction between the stone and light. The way in which the facets of the diamond reflect light determines the cut rating of the diamond. These interactions are:

  • brightness,
  • fire,
  • and scintillation.

Brightness is the white light reflected from the stone. Fire is used to describe the way that the white light disperses into all the colors of the rainbow. Finally, scintillation is essentially sparkle, measured by light and dark reflections on the diamond. Cut is on a five point scale ranging from excellent to poor.

Romance Diamond Co.


Carat is one of the simpler C’s, for it is just the weight of the diamond. A carat is 200 milligrams and can be divided into 100 points, which equals one carat.

100 points = 1 carat

As carat weight goes up, so does the rarity of the diamond. Carat weight is the first factor in determining a diamond’s value.

Learn more diamond terms and tips in our Engagement Ring Vocab blog.