Diamond Certification: A Quick Guide

Unique as they are beautiful, diamonds have distinctive characteristics that determine their clarity, brilliance and fire. Even when their sizes and chemical makeup are exactly the same, these miracles of nature can have subtle and extreme differences. Diamond certification and grading charts provide buyers with insight into a gem, along with the assurance that they are purchasing a quality stone.

What Is a Diamond Grading Report?

No two diamonds are exactly alike. From cut and clarity to color and size, they can have significant differences that work to determine their beauty and value. A diamond grading report describes in detail the important traits of an unmounted diamond, be it naturally mined or created in a lab.

Grading reports include ratings that can help differentiate stones based on fundamental characteristics that determine quality and aesthetic. When determining the grades of a diamond gemstone using the AGS Scale, cut grade is usually first, then color, clarity, then carat weight.

A GIA Diamond is a stone that has been certified by the Gemological Institute of America, the World's premier authority in independent diamond certification. Every GIA diamond is examined by at least four highly trained gemologists who issue ratings for each key trait.

What Do Ratings Mean?

When evaluating diamond cut, a grade is given on a scale of 0 to 10, with a lower number indicating an excellent cut and a higher number suggesting a poorer cut. More than half of issued grading reports are for popular round brilliants, but numerous other complex shapes can also be identified.

For color, the grading scale begins with the letter D, representing a colorless diamond, and continues onward with the increasing presence of natural color. Diamond buyers generally prefer colorless to near-colorless gems, with diamonds graded in the J, K, and L range offering optimal value. When color treatments are detected, asterisks are included next to the color grade.

To indicate the purity and clearness of a diamond, a certified report will also include a rating for clarity. Grades are assigned to a diamond, with "I" describing a gemstone with inclusions and "F" describing perfect clarity. Most diamonds will have grades that range from I to F. Diamond buyers are often willing to select gems with some inclusions, as long as they are not obvious to the naked eye.

What Else Is in a Report?

Certified diamond grading reports are obtained by submitting gemstones for evaluation at third-party grading laboratories. After carefully analyzing a diamond, the laboratories issue detailed grading certificates that include ratings for some critical characteristics, including the all-important 4Cs. They also include some other details, such as:

Grading Numbers

This unique number usually links to a copy of the associated diamond report held by the issuing lab. Often available online, the number is frequently referenced to provide conclusive proof that the issued diamond report is genuine and directly associated with the diamond in question.

Measurement

This refers to a description in millimeters of the length and width (in the case of non-round gemstones) or depth and diameter (in the case of round diamonds).

Polish

Typically ranging from “Excellent” to “Poor,” this rating indicates the degree or quality of smoothness to which diamond gemstone facets have been polished.

You can view an example of a GIA diamond grading report here.

Why Do You Need Certification?

Contrary to common belief, a diamond grading report is not an appraisal; it is a scientific blueprint of a gemstone’s traits. Just as homes have deeds and cars have titles, it only makes sense that people would prefer to seek documentation for an item as valuable as a diamond.

A grading report provides assurance that a gem is an authentic diamond. It also includes written disclosures of any artificial treatments used to enhance color or clarity. From the perspective of intelligent buyers, a diamond grading report provides reliable evidence that promotes a more confident purchase.

With that said, descriptions and certifications won't tell you how a diamond sparkles or reflects light. It also won’t tell you what cut and clarity characteristics mean in terms of beauty and fire. That’s why it’s best to visit a local John Atencio store where our Diamond Experts can show you how to pick a quality diamond that provides the best value for your investment.

Our attentive team always works to ensure that we meet every customer’s unique needs in terms of size, clarity, cut and color, all while maintaining the highest standards. Use our helpful diamond search and then make an appointment at one of our convenient locations.