I did a blog post years ago maybe 10 or so years ago), about a couple of dreadlock wearing white Rasta dudes coming into my shop with a bucket full of that green slag that you find when you walk the railroad tracks. I knew about these rocks, well... because I used to walk along railroad tracks. The RR company poured iron slag into the RR beds before laying the gravel and rails down. It got rid of cheap byproducts from the iron industry, and it made for great drainage for water. It can range from a red to a green glass looking stone, and is totally worthless.
Anyways, these two hucksters were trying to tell me that the green glass was Alabama moldavite. Moldavite is a green glass formed from when a massive meteor hits the earth, throwing up massive amounts of sand into the air and instantly melting it into glass. And, it is only found in Russia, in the areas of woodlands where they have had repeated massive meteorite strikes. It has a special crystalline property that is observable through a moderate strength microscope. But, it can be detected by the naked eye in coloration. Anyways, at the time it was the rage with jewelry designers, as it was a gorgeous green color, but in all truths it is a poor stone for jewelry because it is just glass, and will break easily, even with moderate temperature changes causing thermal shock.
But, these guys were working it, and obvious had a dope smoker's understanding of gems and minerals, siting how Alabama moldavite grows in the ground and keeps growing, and gives of energy... which one day mankind will harness its energy and use it to power their cars. Stupid stuff like that. They were hard sales, but I worked them out the door. And, made sure they didn't steal anything as they left. It was definitely weird.
I have also been on my local pawn shop runs to buy metals when other customers were their with their hard sales pitches, trying to scam the pawn shop owners into buying crap. Scammers are more prevalent than you'd think. But, I think pawn shop guys hear more of the outlandish stuff.
Personally, I don't buy anything anyone tries to bring to me any more. I just recommend them to the pawn shops. Not having a B&M anymore makes it easier. All I have to do now is just hang up on them.