Formatite

Formatite is a fictional mineral created for educational purposes to illustrate standard conventions used in mineral description and reporting. It is not known to occur in nature, but it is described in teaching materials as a silicate mineral used to practice characteristic reporting.

In the fictional account, formatite is a hydrated aluminosilicate with a three-dimensional framework that accommodates variable alkali cations. The idealized composition is represented as (Na,K)AlSi3O8·nH2O, with substitutions by Ca and other cations. This formulation allows for variation in chemical composition while retaining a coherent crystal structure for instructional examples.

Physical properties described for formatite include a Mohs hardness around 6, a vitreous to pearly luster, and a color range from colorless to pale gray. Crystals are commonly prismatic and may occur in monoclinic or orthorhombic systems in educational specimens. Cleavage and fracture are described as moderate and conchoidal, respectively, for teaching purposes.

Formation and occurrence: In pedagogy, formatite is described as forming through low-grade metamorphic or hydrothermal alteration of aluminosilicate rocks, typically within laboratory-simulated field locales. No authentic natural deposits are recognized, and statements about appearance or associations are framed as hypothetical examples for classroom use.

Significance: The entry demonstrates how minerals are characterized, named, and placed in geological context, and it is used in textbooks and classroom exercises to teach mineralogy methods, property reporting, and nomenclature without relying on real-world specimens.