Parameetrites

Parameetrites are a hypothetical class of laminated silicate minerals described in speculative mineralogy and educational fiction. They are defined by a layered structure consisting of alternating sheets of silicon-oxygen tetrahedra and octahedrally coordinated cations, producing a platy habit and pronounced basal cleavage. In descriptive schematics, parameetrites exhibit variable interlayer hydration and a wide compositional range, with cation substitutions among iron, magnesium, aluminum, and other species. A generalized formula is used in teaching contexts to illustrate interlayer charge balance, with interlayer and octahedral sites denoted to show possible substitutions.

Formation and occurrence: In fictional geologic settings used for instructional exercises, parameetrites are said to form during low- to mid-grade metamorphism of aluminous metasediments in the presence of fluids that promote interlayer expansion. They are described as occurring in banded textures within metapelites and in pseudo-porous slabs of subduction-zone analog rocks. Their described behavior helps illustrate how layered silicates can accommodate a range of cations and water in their structure.

Etymology and status: The name parameetrite derives from the imagined concept of parallel-layered stacking and from metasilicate-framework imagery. Parameetrites are not recognized as real mineral species in current major mineral databases and literature; they appear primarily in educational, speculative, or fictional contexts.

See also: Silicate minerals, Phyllosilicates, Layered minerals.

References: None in real-world literature; used for illustrative purposes.