I suspect that dye is added to that mica, probably the Chromium Oxide Green to give it that shade of color.
Edit: sorry, tried to add this to other reply.
pH affects micas made with dye (see
this link)
View attachment 50180
So my guess would be that Chromium Oxide Green is created by adding dye to the mica and it is the pH of soap that is making it morph. I'd send a message to Carrie & kindly ask her for direction in choosing a mica that will not morph, but will retain it's green shade when your soap gels. (Contact NS
link)
Also of interest, and possibly another clue is this (
see link):
Heat effects pH. As heat increases, pH decreases. So that may explain why your columns of soap have no green and only blue, but your heart soap has green. They heated up more, thus lowering the pH enough to cause the blue morph in color. ?? Just a guess on my part, really, but it seems to be what happened.
Did you read all the reviews & pay particular attention to the images posted by the reviewers? I see photos as well as some do mention the blue tint to their soaps. So even though it is a 'green' it does look fairly blue in several of the photos I looked at in the reviews. At least a couple of reviewers noted that their Fragrance Oil (specified which ones) altered the color of Savage Green, so there is another possible suspect that can influence this mica.