Basalt Blobs Should Generate Below y = 0

In the current 1.18 world generation preview, the only stone types that generate below y=0 are Deepslate and Tuff. A third type of stone could add more texture and break up the monotony mining in the deep underground.

Basalt makes an excellent candidate to fill this role. The ashen grey colour of basalt nicely complements the darker colour palette of Deepslate and Tuff. At the same time, Basalt has visually interesting side and top textures that catch the eye.

From a lore standpoint, Basalt makes sense as a choice. There is already precedent for Overworld Basalt deposits because Geodes have an outer layer of Smooth Basalt - Basalt that has been smelted by intense heat.

Furthermore, Basalt makes sense geologically alongside Tuff in the deep underground (they are both igneous rocks).

To sum up, Basalt deposits in the deep underground would look gorgeous in the new caves and add to an immersive mining experience.