Question about Resin

[nekomiao.livejournal.com]

Clear Cast Resin or any kind of resin that's strong enough basically that I can make big things for props like swords/weapons and the like.

I wanted to get some pretty colours going through it and thought this might be the community to ask.

For a weapon much like this one link
or one that looks like an icicle like this one

I was wondering on how to work it. If I trapped a lighter coloured resin inside dark resin or (lightly painted clay inside the darker coloured resin) would it show through because in the first prop it looked like the outside hue is a little darker than the blue streaks on the inside? Or are there any ideas that people can suggest or techniques that have been tried before?

Thanks in advance. =3