Anyway Hoaxland (as he's known on newsgroups.A.F.A-B) says that one of the suitcase bombs was hidden in the Washington Monument during renovations.
I recall from an album of old radio programs that the stone contribed by the Vatican was radioactive, "but wasn't dangerous".
Much like the widening of I-93 in NH a few years ago produced low-level radioactive "waste" in the form of granite rock conventionally blasted out of the way.
For what it's worth.
Was this the same stone allegedly stolen by the Know-Nothings in 1854? Or its replacement?