The GIA will only certify loose unmounted stones, while the EGL offers a grading service for diamonds that are mounted. For vintage and antique pieces, if we think removing the diamond will compromise the integrity of the ring, we will use EGL USA. Otherwise, we send stones to the GIA.
The Gemological Institute of America, or GIA, is the jewelry industry’s most respected diamond laboratory. The GIA is the leading source of knowledge, standards, of diamonds and gemstones. They use the most strict diamond grading process, and generally grading stones 1-2 shades darker than EGL USA. That being said, clarity grades between the two labs are usually comparable