Should the 4C’s of Diamond Grading be updated to 5C’s?

Traditionally the 4C’s of Diamond grading focus upon four general categories of diamond quality that are taken into account during the selection process:

• Carat weight

• Color

• Clarity

• Cut

In my experience, many retail jewelers tend to approach “the cut of a diamond” from the perspective of “diamond shape” when in fact the term “Cut” is used at the trade level to refer to the overall diamond cut quality, which has little to do with diamond shape.

Therefore I propose that a 5th “C” be added to the 4C’s of Diamond Grading, which will encourage the diamond buying public to become familiar with the cut of a diamond as it pertains to both shape and cut quality, e.g:

• Diamond Cut / Shape

• Diamond Cut / Quality

Since I don’t imagine that the 4C’s of Diamond Grading are going to officially be converted over to the 5C’s of Diamond Grading any time soon, let’s discuss the difference between Diamond Cut Quality and Shape.

Starting with shape… which quite simply refers to the shape that the diamond is cut to, this is the outline of the diamond from a top down view, the most popular diamond shapes are round, square, cushion, rectangular, marquise, and oval, with an assortment of “diamond cuts” or “diamond shapes” which are based upon those basic outlines. This graphic provides an outline of the most popular diamond shapes:

While it might seem rather innocent or innoculous to use the classification of Diamond Cut Quality to refer to Diamond Shape when discussing the Diamond 4C’s with the public, the reality is that it enables the retail jewelry trade to gloss over an entire section of diamond grading, which is designed to provide insight into the overall volume of light return and the sparkle factor of a diamond.

I imagine that the majority of the diamond industry prefers to talk about the shape of a diamond with a client, rather than discuss the importance of diamond cut quality, because doing so enables them to sell diamonds of poor cut quality… because I never seem to see anybody who sells poorly cut diamonds talking about diamond cut quality, they always focus on diamond shape in their presentations.

Diamond Cut Quality - The 4th C of Diamond Grading:

The term “diamond cut quality” is used throughout the diamond industry to refer to the overall cut quality of a diamond, which at the most basic level is based upon the polish, symmetry, and proportions grades of the diamond.

At a deeper level, the optical symmetry of the diamond will be taken into account, and will be judged based upon how the diamond appears when viewed through an ASET Scope, an Ideal Scope, and a Hearts and Arrows Scope. The cut quality of the diamond may also be judged upon the manner in which the diamond cutter divided the diamond rough into the three primary sections of the diamond, such as the crown, girdle edge, and pavilion.

Brian Gavin Diamonds recognizes the difference between Diamond Cut Quality and Diamond Shape, therefore all of our Brian Gavin Signature diamonds are submitted to the American Gem Society Laboratory (AGSL) to be graded on their Light Performance grading platform, which uses Angular Spectrum Evaluation Technology (ASET) to measure the brightness of the diamond, and determine the cut quality of the diamond.