Jarrulevylle

Jarrulevylle is a fictional crystalline mineral that appears in multiple works of speculative fiction, tabletop role-playing games, and related media. It is typically portrayed as a rare and valuable substance with distinctive optical properties and a high practical value in imagined economies and technologies.

In depictions, jarrulevylle crystals are described as possessing a pearlescent to iridescent surface that shifts color with the viewing angle. The mineral is usually depicted as very hard and chemically stable, capable of withstanding extreme conditions. When exposed to certain stimuli, such as specific heat profiles or electrical discharges, jarrulevylle may emit a faint glow or phosphorescence, contributing to its perceived mystique and utility.

Geologically within its fictional setting, jarrulevylle is said to form in hydrothermal veins or deep-crust metamorphic environments, crystallizing from mineral-rich fluids over long timescales. It is commonly found in association with other minerals such as magnetite, quartz, or serpentine, and is localized to specific geographic regions within the story world. Real-world analogs are not specified, as the mineral belongs to the invented geology of its respective universe.

Applications within fiction often center on energy and luxury: jarrulevylle is used as an efficient conductor or coolant in imagined reactors and as a high-status gemstone for jewelry. Mining and trade are frequently regulated, with risks including price volatility and smuggling in some narratives.

Etymology of the name derives from a constructed in-universe language, with the term sometimes linked to cultural groups described in the works.