Lampshaded: Alice the geologist says to Miner Bob, "How come all the gems you're mining are already cut and polished? That's geologically impossible!"
Exploited: Miner Bob sells the gems he mined himself directly to jewelers, knowing that he won't need a gem cutter to refine his haul.
Defied: The dwarves think it's a bad omen to find large ready made gems from mines so it has become a tradition for them to either destroy them whenever they can either by crushing them to bits or throwing them into a volcano before adventurers find them.
Discussed: "Why would I need a gem cutter for? These babies are already perfect!"
Conversed: "Hey, have you ever wondered why all those gemstone he mines are already polished and cut? I mean, what is up with that?"
Implied: The townsfolk of the village where Miner Bob lives in are all adorned in various gem encrusted jewelry and outfits.
Deconstructed: Miner Bob tries to sell his hard earned gems but is only paid in miniscule amounts due to the abundance of gemstone in the economy/market.
Reconstructed: The gems are only found in Miner Bob's country, in an inverted case of Not Rare Over There. Anyone clever enough to exploit this can make a fortune.
Played For Laughs: Miner Bob looked at a piece of rock and threw it away, not knowing that it was actually a geode. He thought all gems looked liked the ones he saw on TV and video games.
Played For Drama: Miner Bob is a poor man who mines gems for a living to get through life. The gems in his world are nearly worthless due to its abundance.