Chris,
Have Mom take a web tour of SAA and ArchNet at UCONN -
There's a lot of "wierd" people out there whose livelihood is in bits of
colored glass picked up from the ground.
It reminds me, though, that I hope when restoration crews and craftsmen are
there working around a building and they find these odd bits of glass...they
save them - bag them - note the location and notify someone of their
existence.
How many contractors ignore these tidbits, not realizing some poor slob is
out there trying to historically reconstruct the original fabric - at least
on paper if not in genuine material. Those bits of colored glass tell stories
of the inhabitants and the structure and are pieces of  tangible evidence of
what was.
Much of my undergrad work was in historic archaeological research - finding
odd bits of written history and fitting them into the larger puzzle.

Candy B.