Tetraedrisille

Tetraedrisille is a fictional mineral featured in worldbuilding and speculative geology. The name is derived from the prefix tetra- meaning four, and from the distinctive tetrahedral coordination that is central to its proposed structure.

Structure and composition: In descriptions, tetraedrisille is a silica-rich framework mineral in which fundamental units are SiO4 tetrahedra linked at their corners to form a three-dimensional network. Substitutions of aluminum or boron can occur, producing a variable composition. The material is often described as having a high degree of tetrahedral connectivity, yielding open, porous frameworks.

Physical properties: Hypothetical properties include a relatively low density, high hardness, and excellent thermal stability. The color is often depicted as pale blue, gray, or colorless, depending on impurities. Optical properties are variable, with a high refractive index and strong anisotropy expected from its tetrahedral network.

Occurrence and formation: In fiction, tetraedrisille forms in high-grade metamorphic rocks and in extraterrestrial silicate-rich matrices, or under extreme pressures where tetrahedral networks become locked in place. Its formation is described as requiring conditions that favor corner-sharing tetrahedra over other polyhedra.

History and use: Tetraedrisille has appeared in educational texts and science-fiction writeups as a canonical example of a four-faced silica framework. As a result, it serves as a teaching tool for tetrahedral coordination and network minerals. There are no verified natural specimens, and it remains a hypothetical construct rather than a confirmed mineral species.