Currierite

Chemical formula: Na₄Ca₃MgAl₄(As₅+O₃OH)₁₂·₉H₂O

Currierite is an extremely rare arsenate of the alluaudite group, forming colorless to white, bladed crystals.

## Characteristics Currierite is a very rare mineral of the alluaudite group, a hydrated arsenate of sodium, calcium, magnesium, and aluminum. It occurs as small, bladed or acicular crystals, usually not exceeding 0.5 mm in length. The crystals are colorless to white and form radial aggregates or chaotic clusters on the surface of the host rock. ## Physical Properties Currierite crystals exhibit a vitreous luster. Due to their small size and rarity, many physical properties, such as hardness or density, have not been precisely determined. The mineral is brittle. ## History and Name The mineral was named in honor of Rhiannon and Richard Currier, in recognition of their contribution to the creation and maintenance of the Mindat.org mineral database. It was approved by the International Mineralogical Association (IMA) in 2022 under number IMA2022-003. The type locality is the Torrecillas mine in the Iquique Province, Chile.

Properties

Luster: Vitreous
Streak: White
Cleavage: Perfect on {010}
Fracture: Irregular/Uneven
Transparency: Transparent
Crystal system: Monoclinic

Diagnostic features

## Identification Amateur identification of Currierite is practically impossible. Identification requires advanced analytical methods, such as Raman spectroscopy or chemical analysis using an electron microprobe (EDS/WDS). Visually, it can be suspected based on the crystal habit (fine, colorless needles or blades) and co-occurrence with other rare arsenates at the type locality. ## Distinguishing from Similar Minerals It can be confused with other secondary arsenate minerals of similar appearance, such as pharmacolite, picropharmacolite, or talmessite, which can also form white, acicular crystals. Definitive differentiation is possible only through chemical and crystallographic analysis. ## Crystal Forms Currierite forms elongated, bladed crystals with a rhombic cross-section, often flattened. They occur as single, scattered crystals or form small, radial aggregates.

Geological environment

## Genesis Currierite is a secondary mineral that formed as a result of hydrothermal processes or weathering in the oxidation zone of polymetallic deposits rich in arsenic. At the type locality (Torrecillas mine), it crystallizes in voids within rhyolite rock. ## Mineral Associations This mineral co-occurs with other rare arsenates. At the type locality, it was found in association with anhydrite, lavendulan, picropharmacolite, erythrite, annabergite, gypsum, kankite, scorodite, pharmacolite, torrecillasite, and talmessite. ## Localities The only confirmed occurrence of Currierite in the world is the Torrecillas mine, located near Salar Grande, in the Iquique Province, Tarapacá Region, Chile.

Rarity

Extremely rare

For collectors

## Quality Criteria As a "micromount" mineral, the quality of a specimen is primarily determined by the richness and sharpness of the developed crystals, as well as their aesthetic arrangement on the rock matrix. Specimens with clearly visible, radial aggregates are highly valued. Contrast with the matrix and the presence of rare associated minerals also increase collectible value. ## Popular Localities The only source of specimens is the type locality – the Torrecillas mine in Chile.

Care and storage

## Cleaning Due to its extreme rarity and delicacy, Currierite specimens should not be cleaned mechanically or chemically. Any contaminants are best left undisturbed. If absolutely necessary, compressed air can be used from a safe distance to remove loose dust. ## What to Avoid Avoid contact with water, chemicals, ultrasound, and sudden temperature changes. The crystals are very brittle and susceptible to mechanical damage. ## Storage Specimens should be stored exclusively in specialized, sealed "micromount" boxes, protecting them from dust, vibrations, and direct contact. Display should be in stable room conditions, away from sunlight and heat sources.

Sources

IMA Mineral List (CNMNC)