If you're looking for gems in Nightingale, you likely want to craft cards so you can start exploring new realms. While gems aren't actually part of the recipe, you will need them to craft glass, one of the materials required to build a Simple Enchanter's Focus—the crafting station that lets you make cards.
You may have picked up some gems already from inside chests or while mining other materials. I found Quartz the easiest to obtain in my Abeyance Forest realm, and it can be added to the Smelter to produce glass. With that in mind, here's where to find gems in Nightingale.
