Residualisia

Residualisia is a hypothetical mineral described in theoretical geology and occasional science-fiction contexts. It is portrayed as a rare, dense mineral that could form by residual crystallization during late-stage magmatic differentiation. The name combines residual, indicating a leftover phase, with the conventional mineral suffix -isia.

In proposed models, residualisia is considered metallic or semi-metallic, with a dark, glassy to metallic luster. It is imagined to crystallize in a compact lattice and to exhibit strong magnetic behavior, such as paramagnetism or weak ferromagnetism. The mineral is described as chemically stable under high-temperature conditions but reactive with certain oxidants at surface conditions. No empirical samples exist.

Formation and occurrence: It is hypothesized to originate in ultramafic or mantle-derived rocks where incomplete melting leaves behind a residual phase that concentrates trace elements. If present, residualisia would be extremely rare and localized, potentially occurring as micron-scale inclusions within xenoliths or deep crustal minerals.

Research and uses: As a fictional or hypothetical mineral, residualisia is employed to illustrate ideas about element partitioning, mineral stability, and magnetic properties in theoretical models. In speculative literature, it is sometimes imagined as an energy storage material or catalyst, but such applications remain purely theoretical.

See also: residual entropy, mineralogy, crystal structure.