A diamond certification, also known as a diamond report, is an unbiased scientific evaluation by a third-party of a gemstone’s attributes that guarantees its 4Cs: cut, color, clarity and carat weight. It determines a stone’s beauty, durability, quality and value, and assures its authenticity.
The Gemological Institute of America (GIA) is the industry standard for diamond certification. GIA is the most widely used and trusted name in the diamond trade. It was this not-for-profit organization that created the Four Cs for grading diamonds and the International Diamond Grading System, which developed the common language used today to describe diamonds.
An independent gem laboratory doesn’t sell diamonds and has no connection to diamond mines, dealers or retailers; they have no vested interest in the grade given. At GIA, loose diamonds from D (colorless) to Z (light color), and from 0.15 carats are graded.
Two-thirds of polished diamonds have GIA certification. Among the characteristics that a GIA Diamond Report contains the 4Cs of an individual stone, plus the shape, and specifics of its measurements, table and depth percentages, grade, polish, symmetry, fluorescence, graining and cut grade. A graphic diagram plots the clarity and diamond proportions.
A lab’s reputation is built upon their maintenance of accuracy and integrity. Those performing the evaluations are diamond graders, gemologists and research scientists who’ve gone through extensive training and have passed exams. Several people evaluate a common stone separately; depending on the size of the stone, there may be as many as 40 people scrutinizing and analyzing to reach consensus for a reliable grade assignment. The advanced equipment used in the certification process can detect artificial diamonds and treatments that may have been used to enhance the color or purity of a stone.
A diamond certificate protects the value of your investment, before and after you purchase a diamond. It can help you make an informed decision regarding which stone to purchase prior to payment. It often serves as a prerequisite to securing insurance and an important identifying document in the case of loss or theft post-purchase. Additionally, you’ll need certification to get a fair price if you decide to sell the stone.
TIP: Always check to ensure that a diamond grading certificate will accompany your purchase; it will bring you peace-of-mind.
Diamond certificates should not be confused with a diamond appraisal, which assigns a current market monetary value to a stone.
Here's how to read a diamond certificate.