Fluor-rewitzerite

Chemical formula: [(H<sub>2</sub>O)K]Mn<sup>2+</sup><sub>2</sub>(Al<sub>2</sub>Ti<sup>4+</sup>)(PO<sub>4</sub>)<sub>4</sub>(OF)(H<sub>2</sub>O)<sub>10</sub>·4H<sub>2</sub>O

Fluor-rewitzerite is an extremely rare phosphate mineral, distinguished by its unique chemical composition and occurrence as microscopic, tabular crystals.

## Characteristics Fluor-rewitzerite is a very rare, hydrated phosphate from the rewitzerite group, with a complex chemical composition containing potassium, manganese, aluminum, and titanium. It occurs as very small, thin, tabular crystals, reaching up to 0.2 mm in size, which form rosette-like or spherical aggregates. The crystals are transparent and characterized by a pale yellow color and a vitreous luster. ## Physical Properties Due to the microscopic size of the crystals, many physical properties have not been precisely determined. The Mohs hardness is estimated to be around 2. The crystals exhibit a vitreous luster and are transparent. The density calculated based on the formula and unit cell parameters is 2.41 g/cm³. ## Colors and Varieties This mineral has so far only been observed in one color – pale yellow. No varieties have been distinguished. ## History and Name Fluor-rewitzerite was recognized as a new mineral species by the International Mineralogical Association (IMA) in 2023 (IMA2023-080). Its name refers to the dominant fluorine in its chemical composition and its relation to other minerals of the rewitzerite group. It was discovered in the Jocão quarry, in the municipality of Conselheiro Pena, Minas Gerais state, Brazil. ## Uses Fluor-rewitzerite has no industrial application. Its significance is purely scientific and as a collector's item, as a unique and newly discovered mineral species.

Properties

Mohs hardness
2
Luster
Vitreous
Streak
White
Density
2.41
Cleavage
Perfect on {0001}
Fracture
Uneven
Transparency
Transparent
Crystal system
Trigonal

Diagnostic features

## Identification Identification of fluor-rewitzerite is only possible using advanced analytical methods, such as Raman spectroscopy and chemical analysis (EDS/WDS). Visually, at the occurrence site, it can be suspected based on the presence of pale yellow, rosette-like aggregates of microscopic crystals in association with other rare phosphates. ## Distinguishing from Similar Minerals It can be confused with other microscopic, secondary phosphate minerals of similar color and habit, such as members of the rewitzerite group or other rare phosphates from pegmatites. Definitive differentiation requires specialized laboratory tests. ## Crystal Forms It forms very small, thin, tabular crystals with a hexagonal outline, usually grouped into rosette-like or spherical aggregates up to 0.4 mm in diameter.

Geological environment

## Genesis Fluor-rewitzerite is a secondary mineral that forms in the late stages of crystallization in complex, granitic pegmatites. It originates from hydrothermal processes or weathering acting on primary phosphate minerals in the presence of fluorine-rich solutions. ## Mineral Associations This mineral co-occurs with other rare phosphates. At its type locality (Jocão quarry in Brazil), it was found in association with eosphorite, zanazziite, wardite, brazilianite, montebrasite, quartz, and muscovite. ## Localities The only confirmed occurrence of fluor-rewitzerite in the world is its type locality: Jocão quarry, Conselheiro Pena, Minas Gerais, Brazil.

Rarity

Extremely rare

For collectors

## Quality Criteria As a "micromount" type mineral, the quality of a specimen is primarily determined by the richness and development of the crystal aggregates, as well as their aesthetic arrangement on the rock matrix. The presence of well-defined, though microscopic, crystals within the aggregates is also important. Due to its extreme rarity, every analytically confirmed specimen is valuable. ## Popular Localities The only source of specimens is the Jocão quarry in Brazil, which is known for providing many rare and unique phosphate minerals.

Care and storage

## Cleaning Specimens should be handled with utmost care due to their extreme fragility and small size. Cleaning is not recommended. If absolutely necessary, compressed air can be used from a safe distance to remove loose dust particles. ## What to Avoid Avoid contact with water, chemicals, ultrasound, and any mechanical stress. The mineral is very soft and brittle. As a hydrated mineral, it can be sensitive to changes in temperature and humidity, which may lead to its dehydration and destruction. ## Storage Fluor-rewitzerite specimens should be stored exclusively in specialized, sealed "micromount" boxes, protecting them from dust, shocks, and humidity changes. Avoid exposure to sunlight and keep them in stable room conditions.

Sources

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