There is about as much to say about blue as it is rare. Blue, we all know, is hardly existing in the natural world. A blue pigment is nowhere to be found, creatures appearing blue do so due to structure (and not pigment), and even to fabricate artificially is not all that easy. Nevertheless, the millennia-long quest for a solid, stable blue continues, a quest not entirely without result. As is shown here in this article in Chemistry.
'YInMn blue', accidentally created in 2009, was the first inorganic blue pigment in more than 200 years. photo: Ian Allen / Sciencemag.org