Here is a bit about VRML colors in general and Flux Studio colors in particular. I don't explain color theory here, but instead try to provide an example that you can learn from.
Colors in VRML are based on a Red, Green, Blue (RGB) triplet and have values that vary from 0 to 1. A 0 is zero percent of a color, and a 1 is 100% of a color.
0 0 0 would be black
1 1 1 would be white
1 0 0 would be red
0 1 0 would be green
0 0 1 would be blue
0.8 0 0 would be light red
0.2 0 0 would be dark red, and so on.
Pretty simple there, lets get more complicated...
There are three color components to a VRML material; diffuseColor, specularColor, and emissiveColor. This is how I define them... The color something gives off in scattered light, the shiny color of something, and the color given off by something (like a red hot glowing iron bar).
With careful interplay of these three types of color you can create almost any color imaginable. Practice making various colors and be sure to look at them in a VRML browser, they look different than they do in Flux Studio.
You can right click on this link to download a .spz file that has several glass type colors defined that you may want to use to experiment with yourself. You can also see the embedded .wrl below.
I used 5 or 6 tricks to make my glass materials. Download the .spz file and double click it to run Flux Studio, then....
Click on one of the spheres, in the materials window that pops up, click on edit material and then see...
[NOTE: These colors look a lot better (more vivid) if you have a graphics accelerator card.]