a biface , a two-sided stone tool

[mike]

how do you know the age of this stone tools?

[Minimalist]

Once it is out of its archaeological context you are forced to compare it to other tools which demonstrate a similar style.

[mike]

the archaeological context is the Rocky Necropolis of Pantalica which was added to Unesco's World Heritage List in 2005. see http://whc.unesco.org/en/list/1200 or also http://www.pantalica.org
Unfortunately the site is so neglected that has not been studied enough and it is unknown the age of caves........

[Cognito]

Looks like an acheulian hand axe to me, but hard to say without knowing where it was picked up and its history.

[mike]

it was picked in the rocky necropolis of Pantalica which is dated in the thirteenth century before Christ but the type of stone (flint) does not exist in the area.it could have been brought there by travelers men?

[kbs2244]

Oh boy, you are talking the middle of the Mediterranean.
Other than the Rift Valley of Africa, the most traveled to, and through, part of the planet.

With out real good surrounding, and easily dateable, evidence, you are holding what is politely called an “Out of Place Artifact.”

Good luck

[Cognito]

it was picked in the rocky necropolis of Pantalica which is dated in the thirteenth century before Christ but the type of stone (flint) does not exist in the area.

The material doesn't look like flint to me ... more like chalcedony or jasper. Hard to tell without the original link. KBS is right, without provenance the article cannot be reliably dated.

[mike]

seems to me flint.........

see photo from another aspect