I always felt that there should be some greater purpose for the mermaid gems to give them a higher sell value.
What if there was a treasure item that had three sockets that you could dig up or find, and if you had all three of the mermaid gems, being emerald, ruby, and sapphire, you could slot them into the treasure piece to make the overall value of the item worth more upon selling it.
The item could end up being worth 5000 gold or more upon filling every socket with a different gem.
