Puschridgeite

Chemical formula: Mn₂+(C₂H₃O₃)₁-₂(H₂O)₂

Puschridgeite is an extremely rare, organic manganese mineral, forming microscopic, colorless, bladed crystals.

## Characteristics Puschridgeite is a hydrated manganese lactate, making it one of the few organic minerals. It occurs as extremely small, bladed or acicular crystals, usually not exceeding 0.2 mm in length. The crystals are colorless and transparent, often forming disordered aggregates or fan-shaped clusters on the surface of the host rock. ## Physical Properties This mineral exhibits a vitreous luster. Due to the microscopic size of its crystals, most of its physical properties, such as hardness, density, or fracture, have not been precisely determined. It is a very brittle mineral. ## Colors and Varieties Puschridgeite is colorless. No colored or commercial varieties are known. ## History and Name The mineral's name honors Thomas Puschridge (born 1964), an American mineral collector from Florida, who was the first to notice unusual crystals within the paragenesis from the Pusch Ridge mine. The mineral was described and approved by the International Mineralogical Association (IMA) in 2016 (IMA2016-047).

Properties

Luster: Vitreous
Streak: White
Transparency: Transparent
Crystal system: Monoclinic

Diagnostic features

## Identification Identification of puschridgeite is possible only through advanced analytical methods, such as Raman spectroscopy or X-ray diffraction (XRD), due to its microscopic size and lack of characteristic visual features. Its occurrence in paragenesis with other organic minerals in the Pusch Ridge mine is a key indicator. ## Differentiation from Similar Minerals It may be confused with other colorless, acicular secondary minerals. Certain differentiation from morphologically similar minerals, such as gypsum or other sulfates and organic minerals, requires specialized laboratory analysis. ## Crystal Forms It forms elongated, bladed or acicular crystals, often flattened. Crystals occur as single needles, disordered aggregates, or fan-shaped clusters.

Geological environment

## Genesis Puschridgeite is a secondary mineral, likely formed as a result of post-mining processes. Its organic nature suggests that its formation is related to the interaction of manganese-rich solutions with organic matter (e.g., decaying wooden mine timbers) in a dry, desert climate. ## Mineral Associations It co-occurs with other rare organic minerals such as calclacite, hoganite, paceite, and with ore minerals like chalcopyrite, galena, and sphalerite. Associated minerals also include quartz, barite, and fluorite. ## Localities The only confirmed occurrence worldwide (type locality) is the Pusch Ridge mine (also known as the Pontatoc mine) in the Santa Catalina Mountains, Pima County, Arizona, USA.

Rarity

Extremely rare

For collectors

## Quality Criteria As a "micromount" mineral, the value of a specimen is primarily determined by the abundance and quality of crystals visible under a microscope. Specimens with numerous, well-formed, transparent crystals forming aesthetic aggregates are most highly prized. Association with other rare organic minerals from this locality is also important. ## Popular Localities The only source of specimens is the type locality – the Pusch Ridge mine in Arizona, USA. Collector material is extremely difficult to obtain.

Care and storage

## Cleaning Due to its extreme rarity, brittleness, and microscopic crystal size, mechanical cleaning is absolutely inadvisable. Specimens should be protected from dust and contamination. ## What to Avoid Contact with water, chemicals, ultrasound, and sudden temperature changes should be avoided. As an organic mineral, it may be sensitive to prolonged exposure to sunlight (UV radiation). ## Storage Puschridgeite specimens should be stored exclusively in specialized "micromount" boxes or in sealed containers that protect against mechanical damage, dust, and moisture. Vibrations and shocks should be avoided.

Sources

IMA Mineral List (CNMNC)