Alsete

Alsete is a fictional mineral frequently cited in speculative fiction and world-building exercises. It is not known to exist in real geology, and its properties vary between sources. The term is used to explore ideas about mineral resources, advanced materials, and the ethics of mining in imagined worlds.

Descriptions of alsete commonly portray it as a hard, translucent material with a blue-green hue and a glassy to pearly luster. Its crystal shapes are described as prismatic or tabular, with crystal systems ranging between hexagonal and monoclinic in different narratives. Reported physical properties are intentionally variable, but many depictions assign alsete a Mohs hardness in the upper range and a relatively high density, along with notable optical richness, including strong birefringence when transparent.

Origin stories for alsete differ widely. In some settings it forms under extreme pressures in subduction zones or deep crustal conditions, while in others it is said to crystallize in molten extraterrestrial environments or as a meteoritic inclusion. In-universe geology often treats alsete as rare and valuable, sometimes tied to regional myths or geopolitical tensions around its control.

Applications within fiction commonly include energy storage, high-precision optics, or jewelry. Alsete is sometimes portrayed as having favorable properties for capacitive storage or as a durable, aesthetically prized material. Real-world scientists and educators use the concept to illustrate how materials science might approach unknown minerals, while authors employ it to probe supply chains, regulation, and innovation dynamics in future economies.

Notes: Alsete is a fictional construct and not a real material. See also: List of fictional minerals, materials in science fiction.