marquis cut diamond ring - how to choose a diamond
marquis cut diamond ring - how to choose a diamond

Diamond Rating: A Beginner's Guide


First-time buyers may not understand how diamond rating works. Our guide will teach you how diamonds are graded, so you can choose the best one for you.

12 Minute Read

Gemologists grade diamonds into dozens of categories. Although this helps professionals in the gem trade, the average consumer can find this information confusing. Young couples looking for their first diamond engagement set may find this especially troublesome. While they want to gather enough information to make an intelligent decision, all that data may overwhelm them.

To help consumers make informed decisions, I've divided this article into two parts. First, I'll explain diamond rating and what qualities have the greatest impact on diamond grades. Once you understand that, I'll then have recommendations to help you choose a diamond.

Diamond Rating: What Qualities Matter Most?

You've probably heard of the 4 Cs of diamond grading. I've ranked them below, in terms of importance when you choose a diamond.

  • Cut: The most important property.
  • Color: The second most important property.
  • Clarity: The third most important property, provided the grade is "SI" (Slightly Included) or better.
  • Carat: The least important property.

Now, we'll go through the evaluation of each property.

The Cut

One of the hardest properties to judge, the cut is nevertheless the most important. Choosing a well-cut diamond requires paying careful attention to a few key characteristics....


Donald Clark, CSM IMG

The late Donald Clark, CSM founded the International Gem Society in 1998. Donald started in the gem and jewelry industry in 1976. He received his formal gemology training from the Gemological Institute of America (GIA) and the American Society of Gemcutters (ASG). The letters “CSM” after his name stood for Certified Supreme Master Gemcutter, a designation of Wykoff’s ASG which has often been referred to as the doctorate of gem cutting. The American Society of Gemcutters only had 54 people reach this level. Along with dozens of articles for leading trade magazines, Donald authored the book “Modern Faceting, the Easy Way.”

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