Etenins

Etenins is a fictional mineral described in speculative geology and worldbuilding narratives. It is proposed as a hydrous aluminosilicate with a distinctive layered structure and a shimmering optical dispersion that changes with viewing angle.

Its chemical composition and structure are described as a hydrous aluminosilicate with silicon-oxygen sheets, containing aluminum, magnesium, and minor rare earth elements. In many depictions it crystallizes in the monoclinic system, forming tabular crystals with perfect basal cleavage. The reported hardness on the Mohs scale ranges from 5.5 to 6.5; color varies from pale green to amber-brown; luster is vitreous to resinous; transparency ranges from translucent to opaque.

In the fiction, etenins forms in high-grade metamorphic rocks within subduction-related zones, often in late-stage hydrothermal veins. It is found in deposits associated with quartz, muscovite, and feldspar and is thought to precipitate from silica-rich fluids under moderate temperature and pressure conditions. Notable fictional localities include the Altara Belt and the Veridian Highlands.

In-world uses include jewelry and ornamental carvings due to its color play and luster. It is also studied for potential industrial uses in ceramics and as an unconventional electrolyte component in energy storage prototypes within the fictional setting. Economic value varies with supply in the imagined markets.

The mineral was first described by fictional geologist Dr. Mara Keth in 2053, who named it after the mythical "eten" of balance in several cultures depicted in the lore of Veridia. The name is said to reflect the mineral's symmetrical crossing of cleavage planes in certain crystallographic orientations.