When you shop at internet it has been notified that some certificates have been tampered with to remove the GIA/ IGI / EGL number and security seal.
A lab report not only serves to positively identify the diamond and any treatments that a jeweler or gemologist may not be able to detect, but also enables comparison for shopping purposes with more confident.
Without a report, you could be overpaying for your diamond. Also, could be a possibility that the diamond will be lab-created or has undergone treatments which lower its value.
Most reputable Instituitions for diamonds reports:
Also call certificates for some companies:
Gemological Institute of America (GIA)
International Gemological Institute (IGI)
European Gemological Laboratories (EGL)
These institutions have supreme position in the gemological world, they work closely with jewellers and it is the result of continuous research, support and synergy with professionals and consumers.
Certificated or Report
In 2014, the Federal Trade Commission (FTC) issued diamond grading quality guidelines and recommend not referring to grading reports as certificates. Because implies the grades on the document are facts. And diamond grades, performed by experts, are opinions.