Metalolivine

Metalolivine is a descriptive term used in some geoscience literature to denote olivine-like phases that carry unusually high concentrations of metallic cations beyond the classic magnesium-iron solid solution. It is not an officially recognized mineral species by the International Mineralogical Association, and the term is used informally to describe a range of compositions rather than a single defined mineral.

Composition and structure are variable. Metalolivine refers to olivine-family materials in which cations such as nickel, cobalt, chromium, manganese, or other metals substitute for magnesium and iron in the lattice, producing a metal-rich endmember spectrum alongside forsterite (Mg2SiO4) and fayalite (Fe2SiO4). The substitutions can distort lattice parameters and affect physical properties, but precise endmembers are not fixed. As a result, metalolivine describes a solid-solution concept rather than a discrete mineral species.

Occurrence and formation are limited and context-dependent. Reported instances include laboratory syntheses and experimental petrology studies that simulate high-temperature, high-iron or reducing mantle-like conditions, as well as rare inclusions or exsolution textures observed in meteorites and planetary materials. Natural examples, if present, are typically small and chemically heterogeneous, making external verification challenging.

Significance and status in the literature. The term is used to discuss metal partitioning and redox behavior in olivine-bearing systems, with relevance to planetary differentiation and mantle processes. Because metalolivine is not widely standardized, researchers may classify such materials as modified olivine or as metal-bearing silicates rather than as a separate mineral species.