The Virtuosi: Life in the Infrared
Modified-webcam pictures.
[I]f we get an object hot enough, it will glow visibly. However, warm objects (say, humans, cars, tanks) while not emitting enough visible light to glow, will emit easily detectable infrared light. This makes infrared imaging a handy technology for finding warm things in the dark. And, since many opaque things in the visible are transparent in the infrared (or vice versa), you can dream up a lot of fun to be had if you could only see in the infrared.
Not only fun, but also easy, and I know because I’ve done it, too.
A colorless transparent crystal with a Debye temperature well above the observation temperature can be a remarkably bad black body emitter. White diamond does not visibly glow to 1000 C (reducing atmosphere. Surface oxidation catalyzes fast graphitization). Gem silicon carbide, moissanite, should behave in kind. Dirty silicon carbide resistively heated is an excellent IR source.