Diorite

Diorite is a stone-like material.

Polished Diorite is the polished version of diorite. As with granite and andesite, it can be crafted from regular diorite.

Naturally generated
Regular diorite generates anywhere underground in large veins. It can also be found around the edges of lava lakes, as well as granite and andesite. It is most commonly exposed to the surface in Extreme Hills biomes but can also be found commonly in other biomes.

Crafting
Polished diorite can also be crafted from regular diorite, see below.