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For many years I thought of magnesium as the thing that comes in ribbons which you can light with a match. This common school chemistry class demonstration produces a brilliant white light as the metal burns in air. It is usually followed by a somewhat less brilliant lecture about oxidation.
When I first started hearing about things with magnesium cases, like the famous NeXT cube computers, it seemed a bit odd: I thought maybe they were talking about an aluminum alloy with some magnesium in it. I had a hard time believing when I read they were actually solid magnesium: Wouldn't it be a bit, um, dangerous if you could light your computer with a match? Well, it turns out that magnesium is only easy to light when it's in thin strips or powdered (as a powder it's even used in flash powder and fireworks). In solid lumps, it's actually really, really difficult to light, so difficult that it can take ten minutes with a blow torch to even get it to spark a bit (see below for a story about this).
This is a good demonstration of how the physical form of a substance can have a huge effect on its properties. As a powder magnesium explodes, as a thin strip you can light it with a match, as a bulk solid you may never get the stupid thing lit. Same with corn starch: As a bulk solid you bake with it in a gas oven, as a fine powder it has been known to explode set of by no more than a spark of static electricity (this happens in grain elevators, which do not survive).
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 Camp fire starter.
Commonly used fire starter: You carve off some shavings of magnesium from the block using your hunting knife, then strike the flint with the back of the knife to ignite the shavings. I removed the striker bar (see Cerium for a video of this bar being sparked with a knife). This one was purchased from Walmart in April 2002.
How pure is the magnesium you get at Walmart? Analysis by x-ray fluorescence spectroscopy at the Center for Microanalysis of Materials, University of Illinois (partially supported by the U.S. Department of Energy under grant DEFG02-91-ER45439) gives the following composition:
97.24% Magnesium
1.21% Zinc
1.11% Manganese
0.44% Iron
So, not too bad. It's not reagent grade, but it's decent technical grade magnesium.
Source: Walmart
Contributor: Theodore Gray
Acquired: 15 April, 2002
Price: $4
Size: 3"
Purity: 97.2%
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  Bulk rod.
Bulk magnesium metal rod, about 1.25" diameter. No idea where it's from or what it was used for, but it burns nicely in shaving form. This one was purchased from eBay in May 2002.
Ed Pegg and I spent an entertaining evening burning about 6 inches of one of these bars in two three inch sections.
Click on the story book icon for this sample to see a bunch of pictures of burning magnesium rod. It's not what you expect.
Source: eBay seller magman1000
Contributor: Theodore Gray
Acquired: 29 May, 2002
Price: $6/pound
Size: 1.25"
Purity: >95%
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Engraved plate.
I found a listing for a one inch thick magnesium plate on eBay. It was just a fraction of an inch bigger in each direction than the cover tiles in the periodic table (4.5" by 4.75"). When it arrived, I decided to see if I could machine it into an extra-thick replica of the magnesium cover tile. The edges were easily trimmed to the exact 4" x 4" dimensions of the tile using my compound miter saw (see the construction history page for more about this saw), and I used my tabletop belt sander to give all six faces a nice brushed satin finish.
Then came the moment of truth: Could my engraving machine (see history page) handle engraving magnesium? The answer is yes, with effort. The machine is meant to engrave plastic, and it works great with wood, but magnesium is pushing it in terms of the amount of force needed to move the cutter through the metal. The cutter itself is tungsten carbide and easily able to handle cutting non-ferrous metals. It's more a question of the strength of the pantograph arm. I think it could probably do aluminum and maybe copper, but not much more than that. Harder metals can be engraved using the diamond scratch engraving machine I keep in my office, but it just makes delicate lines, not deep grooves like these.
I applied a coat of clear acrylic varnish, because the metal tarnished almost immediately as I was working it. In fact, I had to put on gloves and go over all the surfaces with the belt sander one last time, because any place I touched it with bare fingers I left tarnish fingerprints. I polished the surfaces and then immediately varnished them to preserve the shine.
Source: eBay seller covers_machining
Contributor: Theodore Gray
Acquired: 29 May, 2002
Price: $8
Size: 4"
Purity: >99%
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Sample from the Everest Element Set.
Up until the early 1990's a company in Russia sold a periodic table collection with element samples. At some point their American distributor sold off the remaining stock to a man who is now selling them on eBay. The samples (excepted gasses) weight about 0.25 grams each, and the whole set comes in a very nice wooden box with a printed periodic table in the lid.
To learn more about the set you can visit my page about element collecting for a general description and information about how to buy one, or you can see photographs of all the samples from the set displayed on my website in a periodic table layout or with bigger pictures in numerical order.
Source: Rob Accurso
Contributor: Rob Accurso
Acquired: 7 February, 2003
Price: Donated
Size: 0.2"
Purity: >99%
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