Bimbowrieite

Chemical formula: NaMgFe<sup>3+</sup><sub>5</sub>(PO<sub>4</sub>)<sub>4</sub>(OH)<sub>6</sub>·2H<sub>2</sub>O

Bimbowrieite is a very rare sodium-magnesium iron hydroxyphosphate, forming microscopic, platy crystals of a yellowish-brown color.

## Characteristics Bimbowrieite is a hydrated sodium, magnesium, and iron phosphate belonging to the palermoite group. It occurs as very fine, platy or bladed crystals, rarely exceeding 0.2 mm in length. These crystals form rosetted or radial aggregates, as well as thin coatings and efflorescences on rock surfaces. Due to the microscopic size of the crystals, its visual features are difficult to observe without specialized equipment. ## Physical Properties Bimbowrieite crystals exhibit a vitreous luster. The hardness and density of the mineral have not been precisely determined due to the small size and rarity of samples. It is a brittle mineral. ## Colors and Varieties Bimbowrieite has a characteristic yellowish-brown to brown color. No varieties have been described. ## History and Name The mineral was discovered at Bimbowrie Station in the Olary Ranges, South Australia, from which its name is derived. It was described and approved by the International Mineralogical Association (IMA) in 2009 (IMA2009-064). The discoverers and authors of the description were Peter Elliott and collaborators. ## Uses Bimbowrieite has no industrial applications. It is solely an object of scientific and collecting interest, sought after by collectors specializing in rare minerals and micromounts.

Properties

Luster
Vitreous
Streak
Pale yellow
Cleavage
Good on {010}
Fracture
Uneven
Transparency
Translucent
Crystal system
Orthorhombic

Diagnostic features

## Identification Identification of bimbowrieite is possible almost exclusively through advanced analytical methods, such as Raman spectroscopy or electron microprobe chemical analysis (EDS/WDS). Visually, under magnification, it can be suspected based on its yellowish-brown color and characteristic platy crystals forming rosetted aggregates. ## Distinguishing from Similar Minerals It can be confused with other secondary, microcrystalline phosphates of similar color, such as cacoxenite or strengite. However, definitive differentiation requires specialized instrumental analysis. ## Crystal Forms It forms thin, platy or bladed crystals, elongated along the [001] axis and flattened parallel to {010}. These crystals combine into radial or rosetted aggregates and form thin coatings.

Geological environment

## Genesis Bimbowrieite is a secondary mineral, formed in the oxidation zones of phosphate deposits in metamorphic rocks. It forms as a result of weathering and alteration of primary phosphate minerals in the presence of solutions rich in sodium, magnesium, and iron. ## Mineral Associations At the type locality, it co-occurs with quartz, muscovite, hematite, goethite, strengite, rockbridgeite, cyrilovite, dziekanowskite, and other rare phosphates. ## Localities The only confirmed occurrence of bimbowrieite in the world is its type locality – Bimbowrie Station, Olary Province, South Australia.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of bimbowrieite specimens is primarily assessed based on the richness and development of microscopic crystals in aggregates. The most prized samples are those with clearly formed, rosetted clusters of intense, yellowish-brown color, contrasting well with the surrounding rock (matrix). Due to their microscopic nature, specimens are evaluated under magnification. ## Popular Localities The only source of specimens is the type locality in South Australia, which makes them extremely rare and desirable for specialized collectors.

Care and storage

## Cleaning Bimbowrieite specimens, typically micromounts, should not be wet cleaned. Dust can be removed very carefully with a soft brush or a photographic air blower, avoiding direct contact with the fragile crystals. ## What to Avoid Avoid contact with all chemicals, including water and acids. The mineral is brittle and susceptible to mechanical damage. Store away from heat and moisture sources. ## Storage The safest form of storage is a specialized micromount box, which protects delicate crystals from dust, shocks, and humidity changes. The specimen should be stored under stable room conditions.

Sources

Read more