Really nice. At first glance I thought it might look better with more crop on the right hand side but after playing with it I think you found the best version. A little more reflection and sparkle in the diamond would have worked well.
A nice background/choice to display the product - provides a very good setting. Composition is good, but the technicals of lighting/contrast could use just a bit of work to really make this stand out. I've discovered that reds are very hard to shoot and adjust in post processing - they tend to "blow" with just about anything you do to them, and not sure how to fix this.