This is a blue sea sapphire, possible the most confusing animal in the ocean. It’s some kind of crustacean that is both invisible and iridescent blue, somehow. I’m going to put my money on magic but the scientists who study this crazy creature have other thoughts, of course.
In the case of blue sea sapphires, these crystal layers are separated by only about four ten thousandths of a millimeter; about the same distance as a wavelength of blue light. When blue light bounces off these crystal layers, it is perfectly preserved and reflected. But for other colors of light, these small differences in distance interfere, causing the colors to cancel out. So while white light is composed of all colors, only blue light is reflected back. This type of coloration is known as structural coloration, and though resembling a gem in hue, a sea sapphire’s color has more in common with an oil sheen than a pigmented jewel. Combine this nifty trick with the sea sapphire’s impressively transparent body, and you have an animal as radiant as a star in one moment, and invisible in the next.
I’m going to think of these as the lightning bugs of the sea unless anyone has a problem with that. No? Didn’t think so. Next I want to see some proof that this is a real animal and not just a piece of cellophane floating in the surf.
Hit the jump for a video.