The scene has been made in Blender. The wood texture is a low quality jpg, because in high resolution, I crashed Octane, even if the used video memory was under 10%.
http://3d-synthesis.com/14-Jewels.html
On my GeForce 8800 GTS 512, it has taken a while. The first image has been rendered in two passes of 16000 samples per pixel (40 minutes each pass) ! The two passes have been mixed with the upper layer at 50% of transparency. Some fireflies have been removed by hand in Photoshop.
This said, tests done at 2048 samples per pixel were rather good.
Beautiful.
