Craig, there are something like 1000 varied forms of Iron oxides. Bond lengths, angles, electron energy levels, quantum effects, all shape the molecules and their reflectivity. Some are short lived forms. Every molecule desires to return to it's laziest condition. The quench can confine? molecules in an "anxious" condition. And they await an opportunity to go to a lower energy state. Sometimes the energy hump to cross is quite high, and sometimes not. Might even have 2 or more humps.
I don't think people are all that interested in coordination chemistry when they just want a pretty blue color.
I know there are many that do not believe in this stuff. But I am in the camp of colors transforming. They seek a lower energy level.
I am reminded of the effort to grow cubic tomatoes, to expedite packing.
