I've seen magnesium burn between two solid blocks of dry ice.  Black
carbon deposits left afterward.

There is a firestarter device, sold by Coleman I believe, which is a
block of magnesium with a strip of "flint" along one edge.
  You use your knife to whittle some magnesium shavings onto a pile of
tinder.  Then you scrape the back of your knife on the flint to make
sparks that ignite the magnesium.

Larry A.
not a chemist, but I used to play one in the classroom

John Rodgers wrote:

> Magnesium - once lit - will burn under water. Heat is so intense and
> chemical reaction so fierce that it splits the oxygen from the water
> molecule for it's own use in combustion. Tough to fight a fire like that
> with water. CO2 extinguishers don't work very well either. The intensity
> of the chemical reaction in the magnesium is such that it also splits
> off the oxygen from the carbon in the CO2 and consumes it. Carbon is the
> leftover byproduct of magnesium combustion and it makes a heck of a
> carbon soot mess. The intensity of the cold of a discharging CO2
> extinguisher might chill the  magnesium sufficiently to reduce and then
> snuff the flame, but I would not count on it. I can't say I have ever
> seen a magnesium fire extinguished successfully- it only went out when
> it burned  itself out.
>
> Regards,
>
> John Rodgers
> 88 GL Driver
>
>
> ROBERT DONALDS wrote:
>
>> I machine the bug cases so I have magnesium flakes that collect over
>> time
>> one night I took a large hand full out into the ally and lit it on
>> fire not
>> very impressive until I kicked it with my boot it then lighted up the
>> ally
>> like daylight and then some funny what a little sturring will do
>> water will not put this out
>> Bob
>>
>>
>> ----- Original Message -----
>> From: "Bill Collins" <wb6otg@INTREX.NET>
>> To: <vanagon@GERRY.VANAGON.COM>
>> Sent: Friday, February 17, 2006 9:00 AM
>> Subject: Re: Firewood
>>
>>
>>> >Wood is nice, but I highly recommend burning an engine case (ala
>>>
>>>> Burning Van 06).
>>>
>>>
>>>
>>> Just make sure no one throws water on it!  Someone did that the last
>>> time
>>> they burned one at Everybus. (I think that's part of the reason it
>>> was the
>>> LAST time)
>>>
>>> Bill
>>>
>>
>>
>