Extrometrit

Extrometrit is a hypothetical mineral concept used in geology and planetary science to describe a supposed high-temperature, high-pressure phase that could form during metamorphic or impact processes. It has no confirmed natural occurrence and is not recognized as a mineral by formal mineral standards.

In teaching and modelling, extrometrit serves as a placeholder for a phase with flexible composition and variable properties that depend on surrounding rock chemistry and the pressure–temperature path.

Descriptions in speculative models typically portray extrometrit as a dense, chemically variable phase capable of broad solid-solution ranges and frequent intergrowths with neighboring silicate or oxide minerals. Its stability is shown to be sensitive to fluid activity and phase equilibria in simulated systems.

Etymology and status: The term extrometrit is a constructed label used in some classroom materials and fictional or exploratory literature; it is not an officially recognized mineral name in standard databases.

Use in education and theory: Extrometrit is employed to illustrate ideas about mineral paragenesis, phase diagrams, and how observational constraints can affect interpretations when a supposed phase cannot be sampled directly.