Fuyuanite
Chemical formula: Mg<sub>7</sub>Nb<sup>5+</sup><sub>6</sub>O<sub>18</sub>(OH)<sub>8</sub>
Fuyuanite is a newly discovered (2023) mineral from the niobate group, forming colorless, microscopic crystals in calcite-dolomite marbles.
Description
## Characteristics Fuyuanite is a hydrated magnesium niobate that forms extremely small, platy crystals up to 100 micrometers in size, usually aggregated into clusters reaching 200 micrometers (0.2 mm). It is a colorless and fully transparent mineral, which, combined with its microscopic crystal size, makes it impossible to observe with the naked eye. It occurs as an inclusion in carbonate rocks. ## Physical Properties The mineral is characterized by a vitreous luster. Its density, calculated based on chemical composition and crystal structure, is 3.73 g/cm³. The Mohs hardness has not yet been determined. It is a brittle mineral. ## Colors and Varieties Fuyuanite is colorless. No colored varieties are known. ## History and Name The mineral's name comes from its discovery locality – the Fuyuan quarry in Shandong Province, China. It was officially approved as a new mineral species by the International Mineralogical Association (IMA) in 2023 under the number IMA 2023-069. ## Applications Due to its extreme rarity and microscopic size, fuyuanite has no commercial or industrial applications. It is solely an object of scientific interest.
Diagnostic features
## Identification Identification of fuyuanite is only possible using advanced analytical techniques, such as energy-dispersive spectroscopy (EDS) to determine chemical composition and X-ray diffraction (XRD) to confirm crystal structure. Visual identification at a macroscopic scale or even under a standard microscope is impossible. ## Distinguishing from Similar Minerals As a colorless, microscopic inclusion, fuyuanite is visually indistinguishable from many other co-occurring minerals, such as calcite, dolomite, forsterite, or diopside. Definitive differentiation requires specialized chemical and structural analysis. ## Crystal Forms It forms thin, platy or bladed crystals that combine into small, rosette-like or irregular aggregates.
Geological environment
## Genesis Fuyuanite forms under conditions of contact metamorphism. It was discovered in calcite-dolomite marbles that underwent alteration due to intruding igneous rocks. ## Mineral Associations This mineral co-occurs with calcite, dolomite, forsterite, diopside, spinel, fluorapatite, and minerals from the pyrochlore group. ## Localities The only confirmed locality of fuyuanite in the world is its type locality – the Fuyuan quarry, in Zaozhuang County, Shandong Province, eastern China.
Rarity
Extremely rare
Collector aspects
## Quality Criteria As a microscopic mineral, fuyuanite is not evaluated according to typical criteria such as color or transparency. The only value for a collector is possessing a specimen of the host rock from the type locality with analytically confirmed presence of fuyuanite. Specimens richer in microscopic aggregates may be considered more valuable. ## Popular Localities The only source of specimens is the Fuyuan quarry in China.
Care and storage
## Cleaning Fuyuanite specimens occur as microscopic inclusions in the host rock (marble), so care applies to the entire specimen. It can be cleaned of dust with a soft brush or compressed air. Careful washing in distilled water is permissible. ## What to Avoid Contact with acids (e.g., hydrochloric acid) should be strictly avoided, as they will rapidly dissolve the surrounding calcite-dolomite marble. The specimen should be protected from ultrasound, high temperatures, and strong mechanical shocks. ## Storage Specimens containing fuyuanite, most often in the form of micromounts, should be stored in closed boxes that protect them from dust and damage. It is not sensitive to light.