Mica is a term used for a group of minerals which are mined, purified and ground into fine powders for cosmetics. It's what gives that special look in eye shadows.
The micas used in soaping are sometimes coated with an iron oxide, titanium dioxide or pigments to give it a more complex or richer color. Sometimes micas used in a cold process soap will morph (change color) so soap makers experiment with different micas to achieved the color they are looking for. The shimmer is lost in cold processed soap when used as a color but using a mica on the top of the soap will create a gorgeous shimmer and unique look.
Below you can see the result of my challenge soap. This soap is made with a strawberry wine in a base of olive, coconut, palm and castor oils with some added shea butter and goat milk. It is scented with a Strawberries and Champagne fragrance oil (phthalate free). I used a merlot mica to create a bit of swirling in the body of the soap with two micas for the top swirls, Merlot and Gold.
This soap will be ready about May 20th as a limited edition.