Prussian Blue was the first synthetic blue pigment - but it seems its role in nature goes even deeper: http://www.sciencedaily.com/releases/2009/12/091214121451.htm? utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A +sciencedaily+%28ScienceDaily%3A+Latest+Science+News% 29&utm_content=Google+Feedfetcher Interesting! KG "Never doubt that a small group of thoughtful, committed citizens can change the world. Indeed, it is the only thing that ever has." - Margaret Mead Need to leave or subscribe to the Sciart-L listserv? Follow the instructions at http://niobrara.unl.edu/users/lana/gnsi/listserv/