Spectrum, known scientifically as thaumachium and historically as cold iron, is an icy blue-white metal produced from thaumarchite ore. Its appearance is distinctive: freshly worked spectrum has a pale, almost luminescent quality that darkens slightly with age and exposure, never quite losing its characteristic cool sheen. For most of Oceanykan history, this visual quality, combined with obscure but observed effects on spiritual practice, made it a prized material for religious artefacts, protective wards, and weapons of ritual significance. The Collegiate of Magicians historically maintained a modest reserve for esoteric instrumentation.

With the scientific study of psionics in the twentieth century came a clearer understanding of what spectrum actually does. Thaumachium-based alloys, including spectrum in its refined form, have a measurable disruptive effect on psionic activity in their immediate vicinity. The mechanism is not yet understood; algeochemical theory proposes that thaumarchite ore has an intrinsic property of dampening or scattering the Dreamspace-adjacent field that psionic ability draws upon. Whatever the mechanism, the effect is consistent and proportional to mass: a spectrum-tipped projectile introduces localised disruption sufficient to interrupt a psionic field momentarily, while a longsword or substantial structural piece will plunge through most psionic defences entirely.

In the current era, spectrum has transitioned from an esoteric curiosity to a material of significant strategic interest. Federal Special Research Division witch-hunter units are equipped with spectrum components as standard. Foreign intelligence services have attempted to acquire samples with varying success; the ore body is, as with all algeochemical materials, exclusively Oceanykan.

This item must be acquired or sold through the black market using Spielkarten.