NASA's Mars rover Curiosity drilled 2.5 inches into a Red Planet outcrop called "John Klein" earlier this month, revealing rock that's decidedly gray rather than the familiar rusty orange of the Martian surface.

"We're sort of seeing a new coloration for Mars here, and it's an exciting one to us," Joel Hurowitz, sampling system scientist for Curiosity at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., told reporters Wednesday (Feb. 20).

Mars gets its red coloration from a surface layer of dust that has undergone a rusting process, during which iron was oxidized.

Curiosity's hammering drill allows scientists to peer beneath that dusty veneer for the first time ever, and the early views at John Klein -- where the rover performed its first full-up drilling and sample-collection operation -- are intriguing, rover team members said.