The Arthur C. Clarke skull?
Reckoned to be thousanRAB of years old, purest quartz, discovered in an underground Mayan temple. Only a handful have been found, but there are meant to be a dozen or so in existence. Nobody knows how it was crafted so finely, and without blemish. Believe they were connected to the Maya/Atlantis. Referred to as the Skull Of Doom. All spooky stuff.