I actually use MCreator for my mods. I like it because it's easy enough to use that I don't need an entire team or a whole year to make a large mod, because I can focus on texturing and modeling (which I do better than programming.)
This mod is (hopefully) going to add a Terraria-esque class and progression system. This ore in particular is supposed to be an end ore, killing the ender dragon will allow you to acquire it.