Not sure I could understand the game I tried mining but didn't seem to do much. I thought it was the triangles maybe? Let me know. Love the art style and seems fun. Did you do a devlog somewhere. I couldn't find it but maybe missed it.
Viewing post in Nomads' Fire jam comments
Dev log is here: https://deathray.itch.io/nomads-fire/devlog/1505602/expanding-the-game
Yes, the things you can mine are the triangles, and sometimes smaller pixel clumps of red, blue, or yellow. You have to blast them for a while, and then check your inventory, and you should see some quantity of an element.