This was an interesting and difficult cover. Jayne and I went through any number of naturalistic images, but nothing really suited.
Then I remembered that a few months before, I had photographed a transparent container filled with wet green (olivine) sand.
The central image is actually a large drop of water with sand grains in it -- that's what gives it its circular shape. The other grains were spread out. Obviously I did some color-shifting to move it into the yellow/red range. Green wouldn't have worked.
The most difficult thing with this cover was removing the horizontal undulations that were in the container's walls. Finally I succeeded.
I'm allowed to have favorites, aren't I? This is one of my favorites.
Five Sextillion Atoms