pienuus

Pienuus is a fictional mineral described in speculative fiction and tabletop role-playing settings. In these works, pienuus is a rare, phosphatesilicate mineral renowned for its vivid bioluminescence and its unusual energy storage properties. When subjected to mechanical stress or rapid temperature change, pienuus crystals are said to emit a pulse of light and release stored energy, phenomena that authors use as a plot device or as a power source for miniature reactors in game mechanics.

The name pienuus is presented within the fiction as derived from an ancient or alien language, with roots imbuing notions of light, resonance, or smallness. Some sources treat it as a compound of a root meaning light and a suffix used for mineral names.

Pienuus crystals are depicted as translucent to iridescent, often hexagonal prismatic forms, with a Mohs hardness of 5–7 and a low to moderate density. In the lore, pienuus forms in hydrothermal veins within basaltic or icy moon environments, where ionized fluids interact with irradiated rock over long timescales.

Within stories and games, pienuus serves as an energy medium, a component in luminescent jewelry, and a catalyst for fictional technologies. It also appears in myths as a symbol of resilience or hidden potential.

See also: fictional minerals, list of minerals in fiction.