The mysterious hunk of metal was found in Romania during the 1970s, when the country was under communist rule.
esearchers have concluded that an early modern human who lived in present-day Romania about 40,000 years ago had a Neanderthal ancestor who lived just 4 to 6 generations back in the individual's family tree.
Used for support during the reparation of serrated iron sickles they bear characteristic serial use wear.
The serrated sickle was an important technical innovation.
Aluminium was not produced by mankind until about 200 years ago, so the discovery of the large chunk that could be up to 250,000 years old is being held up as a sensational find.
Gheorghe Cohal, the Deputy Director of the Romanian Ufologists Association, told local media: "Lab tests concluded it is an old UFO fragment given that the substances it comprises cannot be combined with technology available on Earth." Builders working on the shores of the Mures River not far from the central Romanian town of Aiud found the objects about 33 feet under the ground, where it was buried alongside two bones.