nostrinoste

Nostrinoste is a hypothetical aluminosilicate mineral proposed in theoretical mineralogy as a potential constituent of subduction-zone metasomatic rocks. It has not been observed in natural samples and is not listed in major mineral databases. The name is used in modeling to explore how certain charge-balanced silicate frameworks might accommodate transition metals.

Conceptually, nostrinoste would comprise layered silicate sheets with tetrahedral silicon-oxygen and octahedral aluminum and magnesium ions, interlayer cations, and a framework that supports hydration in interlayer spaces. The proposed crystal system is monoclinic or orthorhombic, with space-group symmetries dependent on cation ordering.

Predicted physical properties include a Mohs hardness in the mid-5s to around 6, a measured density near 3.2–3.6 g/cm3, and a pale blue to green hue in fine-grained aggregates. Optical properties such as refractive index and birefringence would reflect strong anisotropy common to phyllosilicates.

Occurrence and formation: nostrinoste is theorized to form under high-pressure, low-temperature conditions typical of subduction zones, during metasomatic fluid-rock interactions. To date, no analytical evidence has confirmed a natural specimen; verification would require X-ray diffraction, electron microprobe analysis, and Raman spectroscopy on a well-characterized sample.

Significance: as a hypothetical phase, nostrinoste aids in understanding possible silicate frameworks and cation ordering under extreme geochemical conditions. If synthesized, the material could inform ceramic science or serve as a model system for studying layered silicates, though practical applications remain speculative.