Oleskelee

Oleskelee is a term used primarily in speculative mineralogy and in certain science-fiction and fantasy narratives to designate a hypothetical mineral. It is not listed as a recognized mineral by major authorities such as the International Mineralogical Association (IMA) or Mindat.org, and no verified natural specimens are publicly documented.

In fictional contexts, oleskelee is often described as a transparent mineral with a glassy luster ranging from colorless to pale blue. Some sources assign it a hardness around 6 to 7 on the Mohs scale and report prismatic crystals forming in hydrothermal veins or contact-metamorphic zones. Its imagined properties sometimes include energy storage or luminescence when irradiated, making it a plot device in games and novels.

Real-world geologists typically treat oleskelee as a case study in nomenclature and mineral identification rather than a real mineral, using it to illustrate the challenges of classifying hypothetical substances.

Origin of the name and appearances in non-scholarly sources vary, but the term is widely considered fictional outside of speculative contexts.