I'll pick this topic up as I failed again in a quite similar way, the main difference is that this time the colorant was charcoal
The FO behaved horribly too this time, but it cannot be the only problem here.
I did everything just the way you all suggested, mixed the fine charcoal with oil before adding and tried to make sure it's not clumpy, and it actually seemed fine, black and even first. However, when I added the FO it traced IMMEDIATELY, in seconds, and at the same time it went all grainy and even worse than that, the color turned much lighter. The FO obviously caused the fast tracing but the graininess had to be due to the charcoal. There wasn't much to do at that point so now all I have is a piece of mouldy-looking unevenly colored and badly textured "soap" which will quite surely turn out to be horrid
Is the stick blender really the only way to make the mix smoother? I really would not like to make bigger batches to be able to use it and on top of that, I really do not want to buy a new stick blender
EDIT: Okay, now I'll definitely blame the FO even more. I found out this curious thing that happened had a name of its own, ricing. I had never ran across this phenomenon but now I absolutely know what it means and I'm SO going to stay away from that particular FO from now on
So maybe it wasn't so much about the charcoal after all, though I still think it was too grainy. No matter what the soap looks hideous AGAIN, this time it's terrible for real and makes even the "Heart of Stones" look very pretty