Verroille

Verroille is a hypothetical mineral described in speculative geology. In the fictional corpus, verroille forms as blue-green, glassy to pearly crystals that occur in hydrothermal veins within mafic rocks. It is prized by collectors for its distinctive color and rarity, but is not known to have significant industrial applications.

The name verroille derives from the French word verre, meaning glass, reflecting its translucent, glassy appearance. In the fictional literature, it honors the late mineralogist Luc Verrois, who is said to have first documented the mineral in a speculative journal.

According to the fictional record, verroille was first described at Serin Crag in the Merrillon region, discovered in medium-grade hydrothermal veins cutting basaltic andesites. It is typically associated with magnetite, quartz, and chlorite. Formation is attributed to silica- and boron-rich fluids metasomatically altering feldspars at relatively low temperatures.

Verroille is described as ranging in color from deep blue-green to olive, with a pale greenish streak. It has a vitreous to pearly luster and is transparent to translucent. On the Mohs scale it is placed around 6 to 7. Crystals are monoclinic and often display prismatic to tabular habits.

Due to its rarity, verroille has limited economic value and is mainly of interest to mineral collectors and researchers studying hydrothermal processes in mafic rocks. No commercial industrial uses are documented in the fictional corpus.