I never get a moment for this board and this great new AOM
I'm thinking it's the actual rock lately. Having seen so much about how stone, rather than just lay there, has so many properties. Not the least of which are the asteroids bringing all kinds of extra terrestrial things here, and it seemed to be well known by the ancient people seeing how they used them. Our use of Headstones on graves comes from Germanic belief that the stone recorded everything about the dead person it was set above. You are meant to say the names aloud as you walk through a graveyard.
I think the scene from 2001 with the Sentinel stone may be perfectly possible now.Look at psychometry and the uses different stones have when used by us.Not all communication is verbal is it ?