Ejay Weiss

W21st Street-Chelsea

...How about a chunk of "Manhattan Schist" which comprises the geologic bedrock that supports all of the building up of Manhattan...

This particular blend of micaceous minerals is actually named for Manhattan, indicating a specific set of geologic and tectonic forces over millions of years that resulted in this place we now inhabit. I've picked up pieces off the street, and it's probably ground into the cement sidewalk that has flecks of mica in it. Manhattan owes a lot of its upward momentum-not to mention the hollowed-out subway system, to the presence of this humble rock.