Known as Photo 51, it's an X-ray diffraction image of DNA and has at least a claim to be the most important image ever taken.

BBC: The most important photo ever taken?

Using X-ray diffraction will not only tell scientists what kinds of minerals are present in Martian soil, it will also provide clues to what conditions existed on Mars when those crystals formed.

FORBES: Curiosity Gets Its First Taste Of Martian Soil