Rendering diamonds

Hi, I am trying to render the files attached using rhino. But the “diamond” gem is very transparent and the metal underneath almost overlaps the stone when rendering and you can’t see the gem.
How can i make the “gem” “diamond” material less transparent?
thanks
Joana3rdDesignSUN-JC.3dm (2.7 MB) photo3B

First of all your shadow looks very strange. Are you using Rhino 5 or 6

On Rhino6 you need to do 3 Things:

  1. Boolean the Gems from the Metall so there is no overlapping Material
  2. There is a “Bug” in the Renderer that Metall touching the Gems is seen seen through the Gem so you need to move the Gem 0.001 away from the metall
  3. Use the raytrace renderer. The opengl renderer do not render Gems correct.

The final result looks something like this:

Thanks, I am using Rhino 6.
Yes, I moved the stones a little bit and then I could se them.
I will try again!
Thanks