NASA's Mars rover Curiosity has taken its first bite of Martian soil and dug up a mini-mystery for scientists: a bright white speck amid the reddish dirt.

The rover took its first scoops of soil earlier this week — samples of which will be analyzed to determine whether the Red Planet was ever favourable for microbial life — and found the odd fleck in a windblown and sandy area NASA has dubbed Rocknest.

It looks out of place, but scientists said Thursday it's likely native Martian material. It is only one millimetre in size and was spotted after the rover used its mechanical scoop to dig up some dust.

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This bright particle was found in a dusty patch of Martian soil dubbed Rocknest by NASA's Mars Curiosity Rover this week. (NASA/JPL-Caltech/MSSS )

The discovery comes after the team found a 1.3 centimetre-long piece of light-toned material on Oct. 7, which they later determined was debris from the spacecraft itself. But the tiny white granule is likely not a foreign object, scientists said Thursday.

"We plan to learn more both about the spacecraft material and about the smaller, bright particles," said Curiosity project manager Richard Cook of NASA's Jet Propulsion Laboratory, Pasadena, in a statement. 

"We will finish determining whether the spacecraft material warrants concern during future operations. The native Mars particles become fodder for the mission's scientific studies."

Analyzing for signs of microbial life on Red Planet

Curiosity has been scooping samples from "Rocknest," a 2.5-by-five-metre patch.

It used a motorized, clamshell-shaped trowel — one of several tools on the end of its robotic arm — to scoop up a bit of dirt.

Earlier this month, it took its first two samples, which were not analyzed, but were passed through the rover's equipment to scrub its internal surfaces.

The aim was to cleanse the equipment to make sure the sample analyzed was clearly Martian, without any residual materials from Earth.

The third sample, taken on Oct. 16, was picked up by the rover's robotic arm and was the first to be delivered to CheMin, a device that identifies and measures mineral composition, NASA said on Thursday.

More samples will be taken and used to cleanse its other analytical instrument, called the Sample Analysis at Mars, or SAM, similar to CheMin.

Afterwards, later samples will be delivered to SAM, which analyze the material for hydrogen, oxygen, nitrogen and carbon — elements associated with life.

With files from the Associated Press