Deep Purple Carrots are a variety of carrot grown to have the purple/blue pigments that are supposed to help you with memory. They are indeed bursting iwth pigment and will stain other vegetables cooked near them.
I will have to point out that these carrots can have an inedible core that tastes like hard fibers. This is normally the case with larger carrots or those that have been sitting too long. I can't go out and say these a all that great. To be honest I think I'll stick with cabbage for my purple pigments.