Of course, much of the color in these images isn't natural, but instead the result of analysis by a polarizing microscope. But thanks to such analysis we know exactly where these space rocks came from: the solar system's weirdest asteroid.
Generally speaking, when a meteorite hits Earth, we can only identify where it came from in the vaguest of generalities, identifying it either as a relic of the asteroid belt between Mars and Jupiter, of the much more massive deposits of material found beyond Neptune, or occasionally from the Moon or Mars. In this particular case, the precise chemical composition of these meteorites reveals exactly where they came from, as a NASA astronomer explains:
Part of the group classified as HED meteorites for their mineral content (Howardite, Eucrite, Diogenite), they likely fell to Earth from 4 Vesta, the mainbelt asteroid currently being explored by NASA's Dawn spacecraft. Why are they thought to be from Vesta? Because the HED meteorites have visible and infrared spectra that match the spectrum of that small world.
The hypothesis of their origin on Vesta is also consistent with data from Dawn's ongoing observations. Excavated by impacts, the diogenites shown here would have originated deep within the crust of Vesta. Similar rocks are also found in the lower crust of planet Earth. A sample scale is indicated by the white bars, each 2 millimeters long.