Astrobiology and exoplanet science usually treat stellar luminosity, orbital distance, planet size, and atmospheric observables as first-order boundary conditions for habitability. A parallel boundary condition is chemical: planetary systems inherit element and isotope abundance vectors from their natal molecular clouds, which were enriched by previous stellar generations, supernovae, asymptotic giant branch stars, compact-object mergers, and other nucleosynthetic events. This paper develops cosmic elemental inheritance (CEI) and cosmic resource inequality (CRI) as a framework for studying how star-to-star variation in refractory, volatile, bioessential, siderophile, lithophile, radiogenic, and high-Z elements can influence planetary interiors, surface environments, long-term habitability, and the material opportunity space available to technological civilizations. The paper introduces a Kardashev-like but composition-based classification, the Material Potential Scale (MPS), which ranks planetary systems by the estimated accessibility of material resource classes rather than by the energy already consumed by a civilization. The MPS is not proposed as a deterministic measure of intelligence or social development. It is a resource-envelope metric: a way to ask whether a planetary system supplies the accessible materials required for biochemistry, geodynamics, metallurgy, electronics, nuclear power, long-duration space systems, and, as a speculative boundary case, exotic nuclear resources. We define a continuous accessible-inventory formalism, a vector of functional domain scores, and a discrete six-level MPS classification. The framework builds on established results linking host-star abundances to rocky-planet composition, galactic chemical evolution to planet properties, r-process enrichment to actinide inventories, and radiogenic heat to planetary dynamos and geodynamics. We propose falsifiable tests using stellar abundance catalogs, polluted white dwarfs, exoplanet mass-radius demographics, stellar age and Galactic-population information, Eu/Th/U proxies, and models of planetary thermal and geochemical evolution. CRI and MPS should be treated as measurable dimensions of planetary and technosignature studies, complementary to the circumstellar habitable zone, the galactic habitable zone, and energy-based Kardashev classifications. Draft white paper for discussion; version 0.2; 2026-05-03.
Johan E Romero (Sun,) studied this question.