Just to add another quick to the mysterious Meridiani soil:
Where the AIRBAGS pressed on it, the soil is considerably brighter.
Where the WHEELS ran over it, there is hardly any albedo change, not a consistent one at least (there are some light patches in the tracks, to be fair).
So what's going on? Why the huge change in appearance from airbag prints, but not wheel tracks?
The wheels churn and plow where the bags simply pressed and smoothed? The airbags had a static charge and picked up the darker, greyer material from the top? Strange.
It'll be interesting to see if wheel tracks make the hematite go way the same way airbag impressions did.
Meridiani soil -- airbag imprints vs wheel tracks, huh?