Rhombohedraltila

Rhombohedraltila is a hypothetical mineral species used in crystallography and mineral classification to illustrate characteristics of the rhombohedral crystal system.

In theoretical descriptions, rhombohedraltila is defined by a rhombohedral lattice within the trigonal crystal class, with symmetry compatible with space groups such as R-3m or R-3c.

The composition is not fixed; it is posited to lie in the aluminium-titanium-oxygen system, with provisional empirical formulas like Al2TiO5 or related stoichiometries depending on oxidation state.

No physical specimen exists, so properties are speculative. Hypothetical descriptors include vitreous to pearly luster, Mohs hardness around 6, density about 4.0–5.0 g/cm3, and refractive indices in the mid-1.7s.

Formation and occurrence are theoretical; rhombohedraltila is used to illustrate processes like high-temperature metamorphism in rocks containing aluminum and titanium, but there is no reported natural occurrence.

Discovery and status: there is no peer-reviewed description or authenticated type specimen; rhombohedraltila is generally treated as a fictional or demonstrative mineral rather than a confirmed species.

Etymology: the name combines references to the rhombohedral crystal habit with the coined suffix -tila, a convention in invented mineral nomenclature.

In scholarly and educational contexts, rhombohedraltila serves as a case study for comparing crystal systems and mineral classification, rather than as a material with practical commercial uses.