These images were captured by a camera on Curiosity, and reveal the bizarre finger-like structure protruding from the Martian surface and casting a shadow on to the rock below, the Daily Mail reported.
Science buffs have suggested that the small, shiny-looking object, which makes for an incongruous sight amid the rocks, could be composed of material less susceptible to erosion than its surroundings.
A report on Universe Today said that the structure was likely to measure just 0.5cm or less.
It was spotted in the picture beamed back from Mars, which was taken on January 30.
Pictures of the mysterious object emerged after Curiosity drilled its first hole in the surface of Mars, to generate dust it can analyse to detect any traces of life which may once have existed on the planet.
Pictures beamed back from the Martian surface showed a small hole surrounded by a pile of pulverised rock dust, which NASA hopes to use in sample-collection tests.
In a statement the space agency said Curiosity used both percussion and rotation to bore about 0.8in into the Mars rock as a test in advance of a later full drilling to collect samples.
Completion of this "mini drill" test was confirmed in data from Mars received late Wednesday at NASA's Jet Propulsion Laboratory in Pasadena, California.
Mission scientists will now assess the drill cuttings around the fresh half-inch diameter hole to determine whether they are suitable for processing by the rover's on-board lab.
London: NASA's Curiosity rover has discovered a mysterious metal object emerging from rock on the surface of Mars.
First Published: Saturday, February 09, 2013, 12:27