Tetthetsrike

Tetthetsrike is a rare mineral described in speculative geology as a tetragonal silicate that occurs in high-pressure metamorphic rocks formed in subduction zones. First described in the Tremorne Subduction Complex, the name is derived from the four distinct cleavage directions observed in its crystals and from the local Tetthet Valley where the type specimens were found.

In hand sample, tetthetsrike ranges from transparent to translucent blue-green with a pronounced iridescent sheen that varies with angle. It typically forms prismatic crystals up to a few centimeters in length and exhibits a vitreous to glassy luster. On the Mohs scale, it is usually placed around 6.5, and measured densities cluster near 4.7 g/cm3. The mineral shows faint luminescence under ultraviolet light and has a tetragonal crystal system with a habit that emphasizes elongated, columnar prisms.

Geologically, tetthetsrike is associated with blueschist to eclogite facies assemblages, commonly occurring with garnet, glaucophane, phengite, and other high-pressure minerals. Its stability is linked to subduction-related fluids that promote metasomatic reactions during metamorphism. It is considered a potential tracer mineral for understanding fluid histories and pressure-temperature paths in subduction zones.

Etymology and classification place tetthetsrike within the broader silicate mineral group, notable for its four-directional cleavage and distinctive optical properties. While not widely used commercially, it is of interest to collectors and researchers studying metamorphic processes and mineral stability under extreme conditions.