Gemstones are an important part of society in Dierde. They are often used as an essential component in spellcrafting and magic item creation. They are used to adorn gear and of course they are used in trade and for hoards. They are lighter than metal coins while holding more value so you can transport more value for trade easier. There is a bit of homebrew I've used when it comes to gems and so here we will also explore that.
I really do try to make most of this original, but since Forgotten Realms is an integral part of the world I can't help if anything is used without formal permission, but is still "fair use" as I am just using this for my private games.