There is a common misconception that Gundanium is nigh-invincible; this has been disproven by several instances in Gundam Wing and Endless Waltz where the Gundams were damaged, usually by beam weapons. However, this has also lead to the supposition that Gundanium is especially strong against solid weapons, like traditional machineguns (as is the similar alloy Gundarium, from the Universal Century). This second theory may have some truth to it: according to the novelization of Gundam Wing, a physical impact roughly equal to the force of a train travelling at 120 kilometers per hour while towing ten-plus transport cars would be enough to easily destroy Gundanium. This is also covered in the series where Heero attempts to destroy the Wing Gundam with several naval torpedoes detonated simultaneously, although no exact figures are quoted.
Gundanium's name is actually an acronym; it stands for Genetic on Universal Neutrally Different Alloy. The suffix -nium was added to distinguish it from similar alloys being made on Earth. In the After Colony Universe, the word "Gundam" is derived from this acronym (GUNDAnium Mobile suit). Despite this fact, not every mobile suit made with Gundanium is a Gundam (examples: Vayeate, Mercurius).