Schmidite

Chemical formula: Zn<sup>2+</sup>(Fe<sup>3+</sup><sub>0.5</sub>Mn<sup>2+</sup><sub>0.5</sub>)<sub>2</sub>Zn<sup>2+</sup>Fe<sup>3+</sup>(PO<sub>4</sub>)<sub>3</sub>(OH)<sub>3</sub>(H<sub>2</sub>O)<sub>8</sub>

Schmidite is a very rare, hydrated zinc, iron, and manganese phosphate, forming aggregates of microscopic, bladed crystals.

## Characteristics Schmidite is a mineral from the phosphate group, chemically classified as a hydrated zinc, iron, and manganese phosphate. It occurs as aggregates of very small, bladed or acicular crystals, rarely exceeding 0.2 mm in length. Individual crystals are elongated and flattened, often forming radial or tangled felt-like aggregates. Due to the microscopic size of the crystals, its macroscopic features are difficult to observe without magnification. ## Physical Properties Schmidite crystals exhibit a vitreous luster. The mineral is translucent. Hardness and density have not been precisely measured due to the small size and fragility of the crystals. It is a brittle mineral. ## Colors and Varieties Schmidite is characterized by a yellowish-brown color. No varieties have been distinguished. ## History and Name The mineral was approved by the International Mineralogical Association (IMA) in 2018. Its name honors Roland Schmid (born 1966), an Austrian mineral collector who found the first samples of this mineral. It was discovered in the dumps of the "Cornelia" mine in Hagendorf-Süd, Bavaria (Germany). ## Uses Schmidite has no industrial application. It is solely an object of interest for collectors specializing in rare minerals and micromounts.

Properties

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

Diagnostic features

## Identification Identification of schmidite is possible almost exclusively through advanced analytical methods, such as Raman spectroscopy or chemical analysis by electron microprobe (EDS). Visually, under high magnification, characteristic yellowish-brown, bladed crystals in radial aggregates can be observed. ## Differentiation from Similar Minerals It can be confused with other secondary, acicular phosphates found in the oxidation zones of pegmatites, such as cacoxenite or strengite. Definitive differentiation requires specialized laboratory tests. ## Crystal Forms Schmidite forms microscopic, bladed or acicular crystals, elongated along the [001] axis and flattened. These crystals combine into radial or disordered aggregates.

Geological environment

## Genesis Schmidite is a secondary mineral, formed in the oxidation zone of granite pegmatites rich in phosphates. It forms as a result of weathering and alteration of primary phosphate minerals, such as zwieselite. ## Mineral Associations This mineral co-occurs with other secondary phosphates. At the type locality (Hagendorf-Süd), it was found in association with strengite, rockbridgeite, phosphosiderite, jahnsite-(CaMnFe), and apatite-(CaF). ## Localities The only confirmed occurrence of schmidite in the world is its type locality: the "Cornelia" mine in Hagendorf-Süd, in the Upper Palatinate Forest, Bavaria, Germany.

Rarity

Very rare

For collectors

## Quality Criteria The quality of schmidite specimens is assessed based on the richness and aesthetics of the microscopic aggregates. The most prized samples are those with clearly formed, radial aggregates of yellowish-brown crystals, contrasting with the host rock (matrix). Due to their microscopic nature, the purity and size of individual crystals are of secondary importance. ## Popular Localities The only known and most valued specimens come from the "Cornelia" mine in Hagendorf-Süd, Germany.

Care and storage

## Cleaning Schmidite specimens, typically micromounts, should not be wet cleaned. Dust can be removed very carefully using a photographic air blower or compressed air from a distance to avoid damaging the fragile crystals. ## What to Avoid Contact with water, chemicals, ultrasound, and any vibrations or impacts should be strictly avoided. The fragile crystals are extremely susceptible to mechanical damage. ## Storage Specimens should be stored exclusively in specialized micromount boxes that protect against dust, moisture, and mechanical damage. They should not be exposed to direct sunlight or sudden temperature changes.

Sources

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