This is a huge (33.5" x 10" x 4") slab of pure magnesium was probably intended as a billet (stock) to be machined into a part of some sort for a race car, motorcycle, or other such application. I just sanded it smooth and put some varnish on to make stay shiny, then mounted it on a set of cast iron table legs so it could stand upright in my office. Drilling and tapping a hole for a 1/2" bolt in the bottom was child's play: It's softer even than aluminum. And I confirmed that it really is mostly pure magnesium by lighting the chips from drilling the hole.
The slab (which, incidentally, looks a lot like the one in the movie 2001 except not black) weighs 87.5 pounds, which isn't much for a slab this big: Magnesium is pretty light as metals go. If it were made of iron it would weigh 380 pounds, out of tungsten it would be 934 pounds, out of osmium 1094 pounds.
Source: eBay seller boss1
Contributor: Theodore Gray
Acquired: 12 May, 2007
Text Updated: 12 May, 2007