Bauxite Ore
From Pixelmon Wiki

Bauxite ore (left), in comparison to Iron Ore
Bauxite is the new ore introduced in Pixelmon. Its main usage is the manufacturing of the advanced Pixelmon machines.
The easiest way to tell Bauxite from Iron is trying to break it with a Stone Pickaxe. Bauxite can't be broken with it, while Iron can. The color is slightly different as well; it's a little more dull than Iron Ore.
Usage
Bauxite ore is used to produce Aluminum Ingots by smelting it in a furnace.
Location
Bauxite can be found within stone from a height of 41 and up. It is found in abundance in the Extreme Hill biomes and Forest biomes.