Psitanium

Psitanium is a type of psychoreactive quartz-like mineral found throughout the Psychonauts games. It is used as a currency within the game, and has both beneficial and negative affects toward humans in the game's world. It is found in both the physical world and in the mental worlds of other characters.

Physical Description
Psitanium is a glowing purple crystal. It is sometimes found in large clusters, and other times in the form of giant boulders. In Psychonauts, the rock is found in the form of arrowheads.

Properties
Psitanium is said to, in the words of Ford Cruller, "make psychics more psychic," but also "make unstable people more unstable." Otto Mentallis explains that it "reacts to, and amplifies, psychic energy." It also "vibrates with psychic waves." Notably, the town of Shaky Claim was built near Whispering Rock, which led to a large number of people losing their minds, thus resulting in the creation of Thorney Towers.

Psitanium is also shown to have an effect on animals, such as the telekinetic, levitating bears and the pyrokinetic cougars of Whispering Rock, and Mr. Pokeylope, who is able to speak, both verbally and through telepathy, and use psi-blast.

It can be detected via use of a psitanium dowsing rod, which allows the user to pull up psitanium that has been deeply buried.

Psitanium is found in both the physical world and in mental worlds. Notable locations in the physical world include Whispering Rock, Green Needle Gulch, the Quarry, and the Questionable Area.

It is not known how psitanium is drawn from the minds of others.

Uses
Psitanium is used as a currency both in Whispering Rock and the Motherlobe. It can be traded for a variety of goods like psi-cores, dream fluffs, or psi-pops, and can also be traded for devices like dowsing rods and cobweb dusters.

It is also used for its positive effects on psychics. Notably, Ford Cruller's sanctuary was built into a psitanium cavern beneath Whispering Rock, which kept his mind mostly together so long as he stayed inside. The camp was also built into Whispering Rock, as the psitanium helps the development of young psychics.

Psitanium is also used in the creation of psychic inventions, with its psychic vibrations driving the machines. This is notably used in items like the Thought Tuner and the psi-enhanced camera.

Behind the Scenes
NOTE: The information in the following section is non-canon.

A piece of concept art shows psitanium being used as a recreational drug, in particular, depicting Otto smoking a psitanium-laced blunt.