This line is hilarious when paired with the earlier statement:
Oh, I did a fair amount of bullshitting in geology pracs, too 
Well, strictly, if you were able to handle it without 3rd degree burns, you’d bought a chunk of acanthite.
I assumed she knew from a glance because from the second answer, it was a pretty obvious identity. Garnets and mica are both things i think i could identify.
I should add that I didn’t assume it’s the same rock in both panels.
This was decades ago before mineralogists had decided that. It’s the Pluto of rocks and the store labeled it argentite.
Mineralogists have known this since 1926.
- Externally isometric natural crystals of silver sulphide were formed at temperaturese above 180oC, and at ordinary temperature are acanthite paramorphs after argentite.
Gem stores are very liberal with their naming (when not outright peddling woo)
Did they charge at least the silver content of the chunk, or did they not realize its worth?
I think you’re full of schist.
That’s not very gneiss
A sample of garnets in a mica schist:
I mean, I couldn’t identify that since my knowledge of geology is close to zero. But it does look like something that would be trivial for a geologist to identify. The features are pretty obvious.
That’s a rock.
I can identify lots of different geological samples.
Looks like leaverite to me.
It’s been so long I don’t recall what price I paid but I’m sure it was more than the spot price of the silver in it. It was being sold as a specimen after all,
Ok, I’ll play the straight man: “Leaverite?”
Noob rockhound picks up a stone, shows it to the expert. Expert turns it over, eyes it carefully then announces “Leaverite.” Noob says “Leaverite? What’s that? I’ve never heard of it.” Expert tosses it offhandedly away. “Leave 'er right there.”
Bah dum tish. I’ll be here all week. Try the veal. 
I knew the joke; I used it on my scout troop all the time. They never trusted me about rocks after that.
(Their favorite other trivia question is how do you hang a US flag on a wall? Do the blue stars go in the upper left corner or upper right? After a few guesses: Neither, the stars are white.)
I realized as I was typing that from the way you said that, you almost certainly did.
But good bet a few other folks playing along at home didn’t. So consider that explanation for them, not me being patronizing to you. Please. 
An airplane crashes smack on the border between the US and Canada. Where do you bury the survivors?
You bury survivors?
How many animals did Moses bring on the ark?