estlaste

Estlaste is a fictional mineral used in geology-focused worldbuilding and science fiction to illustrate mineralogy concepts. It is not a real mineral recognized by geological science but serves as a model in educational and narrative contexts.

Etymology and definition: The name estlaste is a constructed term, chosen for its phonetic neutrality and lack of real-world ambiguity. In canonical fictional descriptions, it has no fixed chemical formula; writers depict it as a layered silicate with sheet-like crystal structure.

Properties: In standard fictional descriptions, estlaste forms as tabular crystals with a platy habit, a Mohs hardness around 5–6, and a density near 3.0 g/cm3. Its refractive properties are described as producing noticeable birefringence under polarized light. The composition is variable, typically described as an aluminous-silicate with interchangeable cations, allowing a range of colors and trace-element signatures in different narratives.

Occurrence and formation: Estlaste is portrayed as forming under high-temperature, high-pressure metamorphic conditions, often in ultramafic to granitoid rock assemblages within fictional settings such as the Xandrian Belt or analogous regions.

Uses in fiction and education: It serves as a teaching example of metamorphic processes, mineral-water interactions, and the behavior of layered silicates. In some stories, estlaste is also depicted as a source of fictional crystalline energy or as a distinctive construction material within a world’s geology.

See also and references: Estlaste is a fictional construct; there are no real-world references. Related topics include sheet silicates, mineral crystallography, and metafictional worldbuilding.