Muullo

Muullo is a fictional mineral described in speculative literature and games as a translucent, lamellar silicate mineral valued for its energy storage properties. In-world, muullo forms in hydrothermal systems and is mined from veins in basaltic rock.

Etymology and naming of muullo trace to the Muullan language, where mu means light and llo means stone. The name is commonly linked to the mineral’s luminescent characteristics when exposed to electrical stimuli or changes in temperature.

Physical properties of muullo are depicted as those of a layered silicate with prismatic or sheet-like aggregates. Color ranges from pale blue to emerald green, though colorless varieties with internal luminescence are also described. The hardness on the Mohs scale is typically about 5.0 to 5.5, with a specific gravity near 3.0 to 3.4. Muullo crystals can display thin, reflective sheets and sometimes exhibit short, needle-like inclusions that catch light.

Occurrence and formation are described as taking place in fissures within volcanic arcs, formed at moderate hydrothermal temperatures in silica- and alkali-rich fluids with trace metals. Muullo is considered rare, usually found in veins only a few meters across and often associated with other silicate minerals.

Uses of muullo center on energy storage and photonic technologies within its fictional setting. It is depicted as having stable electrochemical properties suitable for solid-state batteries, power cores in advanced devices, and high-efficiency capacitors used in starships and urban infrastructure.

History and cultural significance within the fiction describe muullo’s discovery during a 22nd-century expedition; in some narratives, muullo jewelry and artifacts symbolize resilience and illumination.