Diorite

Diorite is a type of igneous rock.

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

World Generation
Regular diorite generates anywhere underground in rich seams, in an identical way to the other two stone types, as well as gravel and underground dirt. It is most commonly exposed to the surface in Extreme Hills biomes but can also be found commonly in other biomes.

Trivia

 * In real life, diorite is intrusive igneous rock composed mainly of feldspar and small amount of quartz and other mineral. It is extremely hard rock and difficult to carve grand work with. Its extrusive equivalent is andesite.