This is a quick creation (less than half an hour). I was testing blender's daily build and what is a better way to test than to try out some stuff.
I used a simple cube, subdivided it some times and used the experimental true displacement feature. The displacement texture is basically a mixture of voronoi and noise.
The used shaders are a diffuse/glossy mixed with the default fresnel node. And I added volume scatter.
The backdrop is from the free bundle of hdri-haven (https://hdrihaven.com). Thanks Greg for these great hdris!