I am trying to use blender to simulate the Lycurgus Cup. The cup is an example of dichroic (two-color) glass, and appears green when a light source is on the outside of the cup, and appears red when a light source is inside the cup.

Here is an image of when light is outside and it appears green:

Here is an image of when light is inside and it appears red:

I have created a glass cup in blender. I have made the glass a red color, and then used the colorbands under the Object->Material/Shading->Ramps tab to add green specular and diffuse color. However, this makes the glass appear the same mix of red and green whether I put the light source on the inside or outside the cup. An example can be seen here:

According to the second post here, someone was able to

to fake the effect of a dichroic glass in blender rather easily through the use of a magic procedural texture

but they provide no clues on how to do this (in blender).

Does anyone know how to achieve this effect in blender?