In the 2009 film Avatar, unobtanium motivates human mining on Pandora.
The Resources Development Administration, or RDA, seeks unobtanium because it is an extremely valuable fictional mineral. Human operations on Pandora threaten Na’vi communities and the moon’s ecosystem, creating the central economic and environmental conflict of the film.
The word “unobtanium” is a humorous engineering term for a material with ideal or impossible properties, especially one that cannot be obtained. Avatar turns that generic joke into the name of a commercially valuable resource. The film’s story does not present unobtanium as a real mineral found on Earth.
Unobtanium should not be confused with energon from Transformers, dilithium from Star Trek, or spice from Dune. Those are fictional substances from different franchises and have different narrative functions.