Infusion

Infusion is how Stormlight gets taken in. Highstorms generate it, and a gem left exposed to a storm fills with it. Gems on Roshar are usually encased in glass and called spheres, and an infused sphere glows until the light drains away, at which point it is called dun. Spheres light rooms, serve as money, and power Shardplate and fabrials. None of them hold Stormlight perfectly, so all of them fade in time, and Plate drains them faster, faster still once it has been damaged. Very few people can take Stormlight into themselves the way a gem does, and those who can draw it either straight out of a highstorm or out of a sphere. When someone takes it in quickly, wisps of it can be seen streaming off the source.