This is the original screen used ‘Personal grooming appliance’ shiv used by Vin Diesel in the 2000 Scifi/horror hit ‘Pitch Black’
It is made of solid metal and is screen-matched perfectly to all it’s appearances in the film. This shiv was used throughout a great deal of scenes including the climax when Riddick is forced to kill one of the aliens. Aswell as the popular scene where Riddick is seen shaving his head and is confronted by Johns regarding the shiv.
A few examples of the screen matching:
riddickarchive 