re: Impact/shock also causes magnetism.
Interesting and thanks, Nick, Podrock and alcaray. All noted.
Regarding Van Der Wall Forces, it excludes electrostatic interactions of ions, but on Mars... you just can't tell yet especially on the surface (dry winds would have to be accounted for, but that's just me). They have been important with the Voyagers and even Pioneers to study in the viscinity of the Kuiper Belt (but that's another story).
Thanks!
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Aside (I'm pressed for time): Also, most of you may have found out about this: Brownleeite. Very interesting... no oxygen.