Magnesium

Magnesium is a material added by GregTech, NuclearCraft, and Mariculture.

NuclearCraft
Magnesium is a naturally occurring element that is generated as ore in the overworld. In its ingot form it is used as a crafting component in the construction of NuclearCraft machines.

Mariculture
Molten Magnesium from Mariculture is made like so: