This microscopic view, 1 mm across, shows the real colors of the mineral grains in the Lafayette meteorite. The clear and cracked areas are olivine and pyroxene. The rusty and black veinlets are ferroan smectite clays and hydrous iron oxides (ferrihydrite) where the pyroxene and olivine reacted with martian water. These veinlets of clay are martian because: they are truncated by the meteorite's fusion crust, and so are preterrestrial; and 2, have oxygen isotope ratios consistent with martian rocks and inconsistent with terrestrial waters.