Posted 3 months ago
This is one I wish I hadn't sold. Even before I researched abalone nacre, which is a legitimate enigma that fascinates physicists, I was enchanted by the mercuric rainbows in these shells. My last photo is of the surface of ab nacre under an electron microscope. Look closely and you'll see it's made of precisely stacked tiles of a calcium carbonate called aragonite—a substance secreted by the slug—SLUG!—that lives inside this secret firmament. Those tiles are pentagonal, about 10 microns in diameter and .5 microns thick. Their growth is nurtured by by a gum of polysaccharides and protein called conchiolin, also secreted by the slug. It furthermore makes a growth-inhibiting hormone to keep the tiles right-sized. Then—magic. When light enters this nanocrystalline maze of tiles, it is messed with in ways physicists cannot describe with mathematics. They hate that, and study it endlessly. Get this: there is no pigment in aragonite. What you're seeing is purely a result of the nacre's intereference with light waves. Turn the shell one way and it is a wash of glowing purple; turn it again and the purple morphs to green; if you're lucky, there may even be a flash of gold.