rikastasite

Rikastasite is a fictional mineral species commonly used in geology education to illustrate mineral naming and classification. In educational contexts, rikastasite is described as a hydrated silicate-phosphate mineral with a composition dominated by calcium, silicon, oxygen, and phosphorus, and with aluminum and iron as possible substitutions. The empirical formula is not fixed, reflecting typical solid-solution behavior in phosphate-silicate systems.

Crystal system: monoclinic; habit: prismatic crystals or microcrystalline masses; color: colorless to pale green or gray; transparency: translucent; luster: vitreous. Mohs hardness: about 5 to 6; density around 3.0–3.2 g/cm3.

Occurrence and formation: rikastasite is described from hypothetical exposures in the fictional Rikasta region, where hydrothermal fluids altered silica-rich rocks during late-stage metamorphism; it is commonly associated with quartz, hematite, and clays.

Identification and classification: rikastasite is not recognized by the International Mineralogical Association in reality and is used as a teaching example rather than a reported natural mineral. In discussions, it is placed in a phosphate-silicate group for illustrative purposes, highlighting how new minerals are evaluated and named.

Etymology: the name is drawn from the fictional Rikasta region or locality used in educational scenarios to demonstrate naming conventions and the process of mineral description.

See also: list of minerals; International Mineralogical Association; mineral naming conventions.