Natural colourants are what I've been thinking about in terms of soap design.  If the colourant itself has useful properties all the better.  Last year at the CERES market a customer told me about something called shungite.  I'd never heard of it before so did some research on it. And it appears to be most amazing. Wiki describes it as 'a black, lustrous, non-crystalline mineraloid of more than 98%weight of carbon'  It has been used in medical treatment since the early 18th century, and has water purifying and anti bacterial properties.  It is also used as a pigment, which is how I intend to use it in soap.

I ordered the shungite from Russia and then trusted to the system.  My package had a tracking number so I could see how it moved around Russia which was rather interesting in itself.  Then, almost three months to the day, my shungite arrived, the blackest, finest powder. And now the fun begins..  I'm planning a shungite and indigo soap, but just have to work out what essential oils will match it.