For over 100 years, the diamond industry has known about a set of proportions that created the best looking round brilliant diamond. However, despite GIA having published cut classifications in 1953, it wasn't until 2006 that they began to issue a cut grade on their diamond grading certificates. In fact, AGS Laboratories was the first lab in the world to start issuing cut … [Read more...]
Diamond Symmetry and Polish
I would like to credit the GIA because I learned a lot from these two research articles that you can find here and here. In 2012, the GIA updated their rules on grading the following 10 different symmetry parameters: Out-of-round Table off-center Culet off-center Table/culet alignment Table size variation Girdle thickness variation Crown height … [Read more...]
Diamond Grading Certificates
It's important to get a diamond with a certificate and that's about all the advice that many sites give you. Lab reports are important but this tutorial is designed to show you that you simply cannot rely on a lab report for evaluating the cut of a diamond. I know that by this stage, you are more than likely to be aware of at least some of the different labs that grade … [Read more...]
Holloway Cut Advisor (HCA)
The Holloway Cut Advisor (HCA) is a piece of software that was developed by Gary Holloway to help you determine the potential light performance of a diamond. You can access the HCA tool here. The HCA is easy to use. You just simply plug in the information in a diamond lab report and it outputs a score. Unfortunately, the HCA is not a very reliable method of evaluating the … [Read more...]
Light Performance Part 2: Brilliance, Fire, and Sparkle
Light performance can be broken down into brilliance (brightness), fire, and scintillation (sparkle). The unique proportions and the optical symmetry of a diamond will give each diamond a slightly different light performance profile. In part one, I explained why light return is important and why you want to avoid light leakage in a diamond. I also showed you that the … [Read more...]