Here's how this goes:

"What do you do?"
"Oh, I'm a geographer."
"Oh. My brother collects rocks."
"?"

[geobug takes a quiet breath and tries again.]

"You might be thinking of a geologist. A geographer studies the shape of the earth. Not rocks so much. Except the one big one."
"?"
"I make maps."
"Oh! Maps are cool. What kind of maps do you make?"
"I work for an archaeology firm."
"Ah. How many dinosaurs have you found?"
"!?!"

I present my new awesome t-shirt, right off the cafe press: