Does a Magnesium Fork Really Burn?

So last month Rob broke his Manitou Skareb fork, right at the arch. He rode it a few more time, but after suffering a really cool face plant recently he opted to replace. So I found him a new Skareb on eBay, and I got the old one. I disassembled it, and got the two halves of the lowers.
One evening we were sitting out back, and decided to try burning the lowers. I gathered up various files, and we did a little grinding, and found that the magnesium dust will in fact ignite. You can see several of the perpetrators.
I got out the welding torch, and set up a safe area to work in.
Then we decided that maybe we should start with a smaller piece. Fine, I'll get the chop saw. None of the hoped-for pyrotechnics when we cut the leg. We did have a bucket of dirt standing by for fire suppression duties. And a spade.
I adjusted the oxy/acetylene torch and got it lit. I applied heat to the piece of magnesium. But it didn't really light. It just melted a little.
I applied the torch again, but still no ignition. So I dialed the torch as high as I could, and tried again.
We had combustion! The piece of magnesium was burning on it's own. Time to feed another piece into the blaze.
It was blazing nicely. So we just watched it burn from various angles. Burn. Burn. Burn.
Darkness was upon us, so we sat and stared at the blazing white mass. By this time the fire had consumed nearly the entire leg. You could look inside the end of the leg, and see the blaze inside. So we did.
We had a moment longer to look up the leg, and fire was out. It left behind a hot fluffy mass that someone was going to have to clean up in the morning.