NASA's Curiosity Mars rover took another taste of Mount Sharp, a layered parfait of rock and history of Martian environments, and found more acidity than the first bite, according to NASA's Jet Propulsion Laboratory (JPL).

"Our initial assessment of the newest sample indicates that it has much more jarosite than Confidence Hills," said CheMin Deputy Principal Investigator David Vaniman, of the Planetary Science Institute.

Confidence Hills was the area of Curiosity's first sample.

Both areas are part of "Pahrump Hills," a part of Mount Sharp. The hypothesis by the rover's team suggests that the mountain began as deposits of sediment as lakes filled and dried. Mount Sharp is about the size of Mount Rainier in Washington State.

An area dubbed "Mojave," was picked as the first target, due to rice-sized crystals on the rocks. During a test drill, the rock broke, so Curiosity moved on.

A new drilling technique was used - low-percussion - in the area called "Mojave 2."

"This was our first use of low-percussion drilling on Mars, designed to reduce the energy we impart to the rock," said JPL's John Michael Morookian. "Curiosity's drill is essentially a hammer and chisel, and this gives us a way not to hammer as hard."

The powder from Mojave 2 was delivered by Curiosity to the internal Sample Analysis at Mars (SAM) for analysis. The rover might take a few more samples from Pahrump Hills before heading up the mountain.