[@Katakon]

Okay, prism is exactly what I thought it might be. 

Prism is just a shape and is mostly made of glass or common crystal. So no I cannot accept that. 

Fluorite is usually greens, purples and sometimes blue. Clear fluorite is also rarely clear as stated.

If you want the gem on them to be shaped like a prism, that would be fine.
If you want to use a clear gem of a different kind than sure but plan glass or crystal is not really gem like.