you don't just look at it. >> mary schweitzer: touch your tongue to that. >> stahl: she actually wanted to lick it. >> schweitzer: it's supposed to stick like velcro. >> stahl: ah, ew. it did. >> schweitzer: that's bone. >> stahl: that's how you can tell? >> schweitzer: yeah, because the bone's filled with... with little capillaries. and when you put your tongue on it, the moisture from your tongue sucks out the capillaries... >> stahl: this is 80 million years old and it can do that? >> schweitzer: yeah. >> stahl: oh, my god. >> schweitzer: rocks don't do that. >> stahl: the tricky thing about schweitzer's work is that she needs to get her hands on the insides of dinosaur bones, which means literally breaking the bones apart, and sometimes dissolving pieces of them in acid. most paleontologists won't let her near their precious finds. >> schweitzer: jack is the only paleontologist out there who lets me dissolve his dinosaurs. >> stahl: dissolve his dinosaurs. >> schweitzer: yes. >> stahl: you mean ruin them. >> schweitzer: yeah. >> stahl: isn't that considered a little sacrilegious to.