Diamond Glossary

GIA (The Gemological Institute of America) - the foremost gemological lab

WP Diamonds grades its diamonds based on GIA standards. The GIA (Gemological Institute of America) is the leading diamond grading laboratory in the world. While some laboratories have been known to inflate their gradings, the GIA provides reliable, unbiased and accurate diamond certificates. These will detail the 4 C’s of the diamond, along with other information such as diamond fluorescence, polish and symmetry. Each certificate has a unique report number, specific to your diamond.

Girdle - The (usually) narrow area between the crown and pavilion.

The (usually) narrow area between the crown and pavilion on the perimeter of the diamond. The girdle can be as thin as “Extremely thin,” which can be an area of weakness on the diamond, or as thick as “Extremely Thick.”

Grading - How (& by whom) the diamond is graded?

Gemological labs, appraisers and independent gemologists grade diamonds and often provide a certificate or report for that diamond showing the size, shape, color, clarity and other characteristics. Unfortunately, these labs and appraisers each have their own ideas of color, clarity and some other characteristics. As such, a D color, VS2 from one lab could well be graded as an F color SI2 by another lab, or vice versa. This can result in a 50% swing in the value.

WP Diamonds grades all diamonds based on the GIA’s (Gemological Institute of America) standards . GIA is a non-profit organization and the foremost industry expert in grading diamonds. Importantly, we feel they are the most consistent grader and are considered within the diamond industry as being the pre-eminent graders. As such, WP Diamonds is able to offer consistent pricing across the diamonds we value as we can rely on the grading.

So, what if your diamond is graded by another lab? Is it graded incorrectly? Not necessarily. We have found that some other labs are more generous with their grading than GIA, but this is not always the case. We will always review your diamond before giving a final valuation, so you will know for sure what diamond you have.

Graining - lines or curves that appear whitish, colored or reflective.

These lines are caused by irregularities in the crystal growth.