Gem that gets worse when you polish it. The more you do it the worse it gets. If you polish it enough there is a hidden gem inside that sells for a lot.
Combinable gems. If you find all in a set and put them close - they merge into 1.
Gems that age and spoil/get better.
Gems with low friction that slowly drift away and fall from the table.
Gems that whisper you secrets and game tips.
Gems that affect the market price of various other gems based on color.
Gems that boost other gems based on shape - can be controlled by polishing them into that shape.
I knwo thats not a gem but you can make bizmuth type gem
Gem that gets worse when you polish it. The more you do it the worse it gets. If you polish it enough there is a hidden gem inside that sells for a lot.
Combinable gems. If you find all in a set and put them close - they merge into 1.
Gems that age and spoil/get better.
Gems with low friction that slowly drift away and fall from the table.
Gems that whisper you secrets and game tips.
Gems that affect the market price of various other gems based on color.
Gems that boost other gems based on shape - can be controlled by polishing them into that shape.
Living gems that roam around, multiply and die.
Gems that affect your character negatively? Like make them more aggressive or less talkative, which affects the prices?
What about non-gem material that the player needs to determine isn’t valuable?
And maybe some milky gems like opal, moonstone, turquoise.
Tenebrescent gems! Gems that (semi-permanently) change color when exposed to ultraviolet light.