ydinkerrosta

Ydinkerrosta is a fictional mineral described in speculative geochemistry and science fiction to illustrate high-pressure phase relations in planetary interiors. The term appears in theoretical discussions and in world-building narratives as a dense, transition-metal sulfide-oxide solid solution that could form under extreme mantle conditions.

Its proposed composition is variable, typically modeled as a solid solution among iron and nickel sulfide and oxide components, with trace amounts of cobalt and rare earth elements. A representative theoretical formulation is given as (Fe,Ni)(S,O)2, recognizing that exact stoichiometry would adjust with pressure and temperature.

Observed properties in fictional treatments include a high density (roughly 7.5 to 9.0 g/cm3), a metallic to submetallic luster, and a color ranging from dark gray to black. Hardness is envisioned in the Mohs 5–7 range, and crystals are described as forming in high-symmetry systems (cubic or hexagonal) when stabilized by high-pressure conditions. The mineral is imagined to be opaque with a metallic streak.

Occurrence and formation theories place ydinkerrosta in deep crustal or mantle settings, particularly in ultramafic rocks subjected to subduction, or within differentiated planetary mantles where sulfide-oxide melts segregate. In speculative contexts, it may coexist with olivine, pyroxene, and other sulfide glass phases and could participate in conductive networks within the rock.

In fictional usage, ydinkerrosta serves as a tool to discuss mineral stability fields, phase transitions at high pressures, and the potential materials science implications of deep-Earth analogs. It is not known to exist outside of such constructed narratives and has no confirmed specimens in nature.