"Poor girl seems to be losing her mind. She’s always losing that necklace it seems. Makes me wonder why she takes it off at all." - Concerned Mother in regards to how absent minded her daughter has become
Behold, the luminous isle of the Sapphire Eyed maidens
Topaz you say, looks like a good quality citrine to me. I’ll give you 8 pieces of silver for it.
Galvinus driving a bargain.
Fist sized diamond made famous by the thief Tolky. Stole the ‘rock’ from the Archmage Olikan and made it famous when his hidden thief’s den was found and destroyed by Olikan. The rock was never found though and Olikan searches for it to this day.
You find a patch of edible funghi. They taste well and all, no ill effects. UNLESS you consume some beverage, even 3 (three) days after eating it. Then you become really sick with pains, vomiting, all the fancy stuff. As a gift or good meal, it could be a cruel joke or to make sure the heroes spend their time focused on the mission. And the fine soup you had in the inn yesterday could have some in.
(Inspired through a real-world fungus. Was really used to cure alcoholism.)