varoilla

Varoilla is a fictional mineral that appears in science fiction literature and media as a rare crystal with distinctive optical and energetic properties. In many narratives, varoilla forms in high-temperature hydrothermal systems within subduction-zone settings on rocky planets and moons. The name is often described as a combination of a local term for light and a suffix chosen for its musical sound, with no basis in real-world mineral nomenclature.

Physical properties attributed to varoilla vary by author, but common features include a high refractive index and strong birefringence, producing vivid iridescence when viewed from different angles. It is frequently described as luminescent under ultraviolet light, with colors ranging from emerald to sapphire. Some storylines present varoilla as piezoelectric or magneto-optic, enabling unique interactions with mechanical stress or magnetic fields. Crystals are typically depicted as prismatic or tabular, sometimes with faint internal fractures that give them a crystalline “glow.”

Occurrence and mining are usually limited to specialized sites under strict environmental controls, reflecting its status as a rare resource. In-universe, varoilla is valued for several proposed applications, including as a power source for crystal-based engines, a catalyst in exotic chemical reactions, and a luxury gemstone due to its shifting coloration.

See also: Fictional minerals, Crystallography in fiction, Photoluminescence in literature.