Bauxite

Bauxite is a material added by various mods.

GregTech 5
Bauxite is the primary source of Aluminium and Titanium.

Engineer's Toolbox
Bauxite is the only source of Aluminium. Bauxite can be directly smelted into Aluminium Ingots.

Tech Reborn
Bauxite Ore spawns between Y-level 10 to 60, with a vein size of 6 and 10 veins per chunk.