I knew it was going to discolor to a dark brown, so I reserved a portion of the soap batter and colored it with orange mica (no fragrance added). Then I poured them, alternating, into the mold. After pouring, I gave a quick whirl with a spoon. The orange mica part looks pink in the picture, but it's actually more peachy/light orange.
after one week (I cut the textured top off of one bar)
In other news, I bought two silicone molds I found in the Halloween clearance section for $1.75 each. I'm sure they'll come in handy some day!