I didn't either, but it's pyrophoric just like magnesium is. You have to get it a bit hotter before it catches, but it'll burn.

Another interestingly pyrophoric metal is uranium. That's why use of depleted-uranium munitions creates such horrible birth defects: not because they create nuclear explosions, and not even because they're horribly radioactive; but because frequently when a depleted-uranium penetrator strikes, it gets hot enough to burn, which means that clouds of uranium oxide get into the air and soil and water and are ingested by people and animals in the vicinity. Mostly, that causes standard heavy-metal chemical poisoning; but there's also a bit of radiological damage, because even a not-particularly-radioactive isotope like U-238 can cause problems if it's actually inside your body.

"But whether the Constitution really be one thing, or another, this much is certain--that it has either authorized such a government as we have had, or has been powerless to prevent it. In either case, it is unfit to exist." --Lysander Spooner, 1867