The first rock to be touched by NASA's Curiosity rover - dubbed Jake Matijevic - turns out to have a very Earth-like composition, different to anything before seen on Mars.
The rover team analyzed two penny-sized spots on the rock using the arm-mounted Alpha Particle X-Ray Spectrometer (APXS) instrument and the Chemistry and Camera (ChemCam) instrument.
"This rock is a close match in chemical composition to an unusual but well-known type of igneous rock found in many volcanic provinces on Earth," says Edward Stolper of the California Institute of Technology.
"With only one Martian rock of this type, it is difficult to know whether the same processes were involved, but it is a reasonable place to start thinking about its origin."
On Earth, rocks with this sort of composition generally come from processes in the planet's mantle beneath the crust, from the crystallization of relatively water-rich magma at high pressure.
"Jake is kind of an odd Martian rock," says APXS principal investigator Ralf Gellert of the University of Guelph in Ontario. "It's high in elements consistent with the mineral feldspar, and low in magnesium and iron."
Meanwhile, NASA's done something rather surprising with its first scoop of Martian sand.
"Yestersol, we used Curiosity's first perfectly scooped sample for cleaning the interior surfaces of our 150-micron sample-processing chambers," says Chris Roumeliotis, lead turret rover planner. "It's our version of a Martian carwash."
Curiosity's spending about three weeks at the sandy spot called Rocknest; next, the team plans to drive it about 100 yards eastward and pick a rock as the first target for the rover's drill.