That radianite must be ours!
— Cypher (Barrier Down)
Radianite is a substance that has become a major part of Earth's civilization after its discovery.
Although little is known about it, radianite is thought to have something to do with Dark Matter. Its effects were initially known to be a clean, safe source of energy and something that could inflict supernatural abilities upon certain people who come into contact with it. Known as Radiants, they made up only a relatively small section of the global population and eventually became an accepted part of society. Though at first they were thought to only have limited levels of power, an incident in Venice revealed that there existed a rare few with very high potential.
Radianite is used to power and augment much of Earth's technology. Some devices require a Radi-Core, a cube that contains solid radianite, to be powered, such as Killjoy's turret. A Radi-Core can be super-heated to liquefy the radianite inside, which will cause it to generate even more power. Radianite technology also offers a multitude of "space faring opportunities".
Radianite has also been spotted on the various maps, all of which are radianite-inflicted locations. Radianite is seen to be stored in green containers found on differing locations on each map (usually at planting sites).
After the disaster in Venice, it was revealed that radianite had more destructive potential, leaving the world questioning how safe radianite actually was.
The Kingdom Corporation has been known to use force to collect, process, and store large quantities of radianite. After just 10 years since First Light occurred, they had grown enough to be able to produce three quarters of Earth's energy. They claim that radianite is beyond safe, despite the concerns of many after incidents such as the Rise of Venice.
Radianite Points are used as an in-game currency, used to purchase upgrades to Weapon Skins and unlock variants. It is unknown if the use of RP as a currency in game corresponds to any existing currency within the lore.
The Ultimate Orbs placed around the maps are also radianite constructs.