It looks like aluminum, my bad, still that's the one I would have him ride, why...do you really want to know why? While magnesium may be 20% lighter than aluminum for a given strength, but it's only about 65% as stong/weight compared to titanium; it's a *****e to weld or machine on due to fire concerns; will corrode but of course paint will protect it as long as the paint remains intact, once corrosion starts the frame is will die quickly; and it will react with steel bolts; it will crack in an accident instead of bending; though it would produce some great sparks if a car dragged it down the street. I'm sorry, but I want a practical bike, Loosespoke can ride the impractical one. But hey, I had to pick on a bike, personally I would buy some cheap bike from Walmart and have Loosespoke ride it!!!! OK, now I'm being mean.