The only hole I couldn't knock out was the one around a flat, essentially 0% return.

FORBES: Break Their Crystal Balls

The sample comes from a hole about 2.5 inches deep drilled on Feb. 8 in a flat plate of sedimentary bedrock that the space agency managers have named "John Klein" in memory of a Mars Science Laboratory deputy project manager who died in 2011.

WSJ: Rover on Mars Extracts First Rock-Core Sample