It is important to have your diamond certified by a reputable and independent laboratory to ensure an unbiased evaluation of the stone’s quality. The Gemological Institute of America (GIA), HRD, International Gemological Institute (IGI), and European Gemological Laboratory (EGL) are among the leading grading bodies in the diamond industry, and are listed in order of strictness. Today, most diamonds over 0.20 carats are typically graded by one of these labs.

Expert Tip #1: Because small differences in diamonds can have a significant impact on their price, sellers may offer self-certification or certifications from less stringent local grading bodies to increase their margins. Keep in mind that comparing these diamonds to those with internationally recognized certificates is not an apples-to-apples comparison. To ensure a level playing field, it is important to demand a recognized international certificate.

Expert Tip #2: Even among the 5 internationally recognized certification bodies, there are differences in the standards they use. The diamond industry often uses the strict standards of the Gemological Institute of America (GIA) as a benchmark. Comparing a diamond with a GIA certificate to one with an IGI or EGL certificate is not an equal comparison, as a diamond graded by EGL would typically receive 2/3 lower grades if it were graded by GIA.

Laser Inscription: The five leading diamond certification organizations issue a unique number for each diamond to protect consumers. This number is often laser inscribed on the girdle (the narrow band around the diamond’s circumference) of the diamond, and can be easily verified with a magnification loop. This helps to ensure that the diamond you are purchasing is the actual one. Laser inscription is commonly found on most new GIA certificates and selectively on some other certificates.