Jétonne
Jétonne is a term commonly used in speculative fiction to denote a rare mineral with exceptional energy storage and luminescent properties. In different works it is described as a crystalline material capable of releasing or storing large amounts of energy with minimal heat generation. The word has no single canonical definition, reflecting its role as a versatile world-building device rather than a real scientific substance.
Etymology in fiction often ties jétonne to invented mining histories or to French-language naming conventions, but
Properties attributed to jétonne vary by narrative, but common descriptions emphasize high energy density, structural hardness,
Occurrence and extraction in stories place jétonne in secluded deposits—deep underground, in mountainous belts, or on
Applications and cultural impact also differ by author. Jétonne may power propulsion systems, superconducting devices, or
See also: fictional minerals, resource scarcity in science fiction, rare earth element analogs.