Do You Know About Diamonds?

I've shopped for lab diamonds quite a few times. But, I know nothing about them. So, I start with a site beyond4cs guide to buying the best proportioned diamond. He has one for every shape. So, on paper my diamonds would be top of the line. However, that's not the case. Supposedly diamonds even great cut ones can still have issues. All the diamonds I've bought have 360 videos, so I can see them spin. To be honest, I don't notice much wrong with any of them. However, from still photos, most I just pass by.

I had this ring made for my wife a few years ago. It's based on a ring we used to see in Macy's Estate Jewelry window. When my wife opened this she said "the band of onyx should have been narrower". It's a 2.4 carat diamond in platinum.

This is my version of a flashlight test on the diamond. If you know about diamonds, how would you rate this? If you notice something, please let me know.

I just want to learn to pick the best. Not just by the numbers. By actually noticing what I'm supposed to.