Oh, those look vastly better! Yes, that is an important consideration that deserves mention in the docs. So, each gemstone must be a separate mesh within a model - or must be a separate model? Does axis orientation affect the result? (Is the shader, say, expecting a local axis with Y pointing up at the crown/table for best result?)
You are correct, my example gems are currently exported directly from the CAD program as a combined mesh… and these rings have several, sometimes dozens of accent stones. Hmm, ok, more pipeline work to be done.