Advice: How to get the color for a Diablo Soulstone?

I'm trying to think of ways to get the right coloring for this:


I can get a black resin color, even a slightly translucent one. Just looking for ideas on how to get inner colors. All I've come up with so far is adding crumpled colored cellophane to the resin, which probably won't be very accurate.

Note: I'm not actually sure that this isn't just a black crystal with a fire reflecting off of it, but someone wanted a crystal that looks like this and believed the crystal itself had multiple colors. I've never played the game so I'm trusting them.

Any ideas? Thanks!!

This picture shows that there are candles at the sides lighting up the crystal, I'm guessing it also have a little Red hue to it.

If using tints in resin, then you would need to cast it in parts where the black parts have less opacity than the part that need to let light through. You could even add a yellow or red tint resin to other parts and then light the whole thing from underneath. Not an easy prop.