Rayleightalet

Rayleightalet is a hypothetical mineral used in discussions of mineralogy and materials science to illustrate a layered, anisotropic silicate with optical and mechanical features that challenge simple classification. It is described in theoretical contexts rather than as a confirmed natural specimen.

The name is a coined term combining references to wave phenomena (Rayleigh) and a suffix used in mineral nomenclature. It was introduced in a 2012 theoretical study that proposed a stable, tetragonal layered framework that could form under hydrothermal conditions. The designation serves as a model for exploring how layering and coordination influence physical properties in silicates.

Structure and properties. Rayleightalet is described as comprising alternating sheets of tetrahedrally coordinated motifs linked to octahedral layers, yielding strong directional dependence of properties. Predicted attributes include pronounced birefringence, brittleness, Mohs hardness around 4–6, and a modest density in the range of 2.8–3.4 g/cm3. The material is also anticipated to behave as a semiconductor with a moderate band gap.

Occurrence and synthesis. There are no confirmed natural specimens of Rayleightalet. In laboratories, researchers have reported synthesizing analogous layered silicates under hydrothermal conditions at temperatures of 350–600 C and modest pressures, though stability is often limited to laboratory timescales; ambient conditions typically promote transformation to related phases.

Significance and status. Rayleightalet functions as a useful model system for studying two-dimensional layering, anisotropy, and phonon transport in silicates. While it is cited in theoretical works and methods-oriented studies, there is no consensus that a naturally occurring or commercially recoverable sample exists, and practical applications remain speculative.