Diorite is a stone-based igneous rock that is in the Overworld, it can be found in large pockets in the ground and in mountains. It can be mined with any pickaxe and it is naturally generated in large blobs.
A block of diorite (via shotgun)
Diorite is generated in the form of blobs in the Overworld. It is most commonly found underground, in caves, and in mountains. Diorite can also be found in the houses of weaponsmiths, tanners, and masons in snowy tundra villages. You can pick up diorite blocks by breaking them with any type of pickaxe.
Diorite found in a cave (via screenshot)
Diorite is currently used only for decoration and it has the same blast resistance as stone, meaning it can be used as a substitute for stone when building. They can be polished, and cut into stairs and slabs with the help of a stonecutter.
Diorite is a block that is similar to stone and is mostly used for decorations and construction purposes. It is abundant in the overworld making it quite easy to obtain.
A. Diorite is extremely common between Y levels 0 and 79.
A. You can make diorite with 2 cobblestones and 2 nether quartz.