menotilit

Menotilit is a hypothetical silicate mineral used in educational contexts to illustrate mineral classification and crystallography. It is described as a hydrous aluminosilicate with sheet-like morphology.

Etymology and naming: The name combines 'meno-' from the Greek menos meaning 'month' and '-lit' from 'lithos' meaning stone, chosen by convention in mineralogy for fictional specimens. It has no official recognition.

Physical properties: In the hypothetical description, menotilit crystallizes in the monoclinic system, forms tabular crystals up to 1 cm, and has a vitreous to pearly luster. Mohs hardness around 4–5; color varies pale green to gray; measured refractive indices around nα=1.60, nβ=1.62, nγ=1.64. Pleochroism weak.

Chemical and structural features: The proposed formula is a hydrated calcium-magnesium-aluminum silicate with approximate composition (Ca,Mg,Fe)2Al4Si6O20(OH)4, with trace rare earth elements. It is described as a layered phyllosilicate with octahedral sheets of aluminum and magnesium between tetrahedral silica sheets.

Occurrence and formation: In the fictional scenario, menotilit forms during high-temperature metamorphism of basaltic rocks and develops in hydrothermal zones associated with serpentinite. It is imagined to coexist with minerals such as wollastonite, diopside, and serpentine.

Uses and significance: As a hypothetical mineral, menotilit is used in teaching mineral classification, X-ray diffraction interpretation, and phase equilibria. No commercial deposits are known; research is limited to classroom demonstrations and speculative scenarios.

See also: Silicate minerals, Phyllosilicates, Mineral classification.