|Metal type||God Metal (Odium)|
|Featured in||The Stormlight Archive|
Raysium is a bright golden metal, so light it is almost white.
Raysium can naturally conduct Investiture, drawing it in from any source. This applies to all of the Lights, but also to spren - allowing someone to transfer spren between gemstones, including spren halves produced during the creation of pairing fabrial.
As raysium has no known physical properties, most of its uses have to do with its ability to conduct Investiture.
Odium's forces have been using raysium in weapons for several Returns leading up to the True Desolation, utilizing the metal's Investiture conductivity to drain enemy Radiants of their Stormlight, and also fill gems with Light. The spears used by the shanay-im during the True Desolation are likely such weapons.
Soon after the imprisonment of Ba-Ado-Mishram during the False Desolation, a Fused known as She Who Dreams realizes that raysium could also be used to direct the soul of a Herald to a gemstone prison. At least a few such soul-harvesting daggers have been created in the years since - the knife used by Vyre to kill Jezrien is one of them, and Raboniel is in possession of at least two more during the occupation of Urithiru: one she uses to permanently kill her daughter (and is later used by Navani to mortally wound the Lady of Wishes herself), while the other is charged with anti-Stormlight and given to Vyre to eventually be used against Phendorana. Yet another such knife is given by Mraize to Shallan so she can collect the soul of the Herald Kalak for the Ghostbloods.
Raysium has no known uses in cage construction, but its ability to transfer Investiture - spren, specifically - from one gem to another allows for a half-spren trapped in one half of a conjoined pair of gems to be transferred to another gem, not part of the original pairing. This can lead to an asymmetry between the movements of the two spren halves, as moving a larger gem a certain distance will now make its smaller paired counterpart move a larger distance.