Tuolien

Tuolien is a fictional mineral described in speculative geology and science fiction. In the stories and worlds where it appears, tuolien is a rare silicate mineral noted for its vivid iridescence, which is attributed to nanoscale lamellae that produce constructive light interference. The composition is portrayed as variable, with magnesium and iron substituting at several sites and trace elements responsible for color diversity.

Crystal form is described as prismatic to tabular, with a hexagonal habit in some depictions. Physical properties often cited include a hardness around 6 on the Mohs scale, a refractive index near 1.70 to 1.75, a vitreous to resinous luster, and strong pleochroism, meaning the color changes with the viewing direction.

Geological context within fiction places tuolien in high-temperature, high-pressure metamorphic settings associated with ultramafic rocks. It is sometimes linked to metamorphic aureoles surrounding ancient subduction zones and to fantastical geologic histories in the narratives.

Use and significance in fictional worlds vary. Tuolien is commonly depicted as a coveted gem for jewelry and ornamentation, valued for its color play and rarity. In some works, its lamellar structure is explored for potential photonic or energy-related applications within the story’s technology, contributing to worldbuilding around science and industry.

Origin of the term and its naming are tied to fictional geologists and regions created by authors, with tuolien appearing across multiple novels and media within the same imagined universe.