Goldquarryite

Chemical formula: Cu<sup>2+</sup>Cd<sup>2+</sup><sub>2</sub>Al<sub>3</sub>(PO<sub>4</sub>)<sub>4</sub>F<sub>3</sub>·10H<sub>2</sub>O

Goldquarryite is an extremely rare, blue phosphate mineral, known exclusively from a single locality worldwide.

## Characteristics Goldquarryite is a hydrated copper, cadmium, and aluminum phosphate, occurring as microscopic crystals. It forms characteristic radial aggregates or small, spherical clusters composed of acicular or platy crystals. Its size is typically very small, and specimens rarely exceed a few millimeters in diameter, making it a mineral primarily accessible to micromineral collectors. ## Physical Properties This mineral is very soft, with a Mohs hardness of approximately 2. It has a vitreous luster and is transparent to translucent. Its density, calculated from the chemical formula and unit cell parameters, is 3.13 g/cm³. ## Colors and Varieties Goldquarryite occurs in a uniform, light blue or sky blue color. No color varieties or commercial varieties are known. ## History and Name The mineral's name comes from its discovery locality – the Gold Quarry gold mine in Eureka County, Nevada, USA. It was approved by the International Mineralogical Association (IMA) in 2010, and its first description was published in 2011. This is the only known occurrence of this mineral in the world. ## Applications Due to its extreme rarity and microscopic size, goldquarryite has no industrial applications. It is solely an object of scientific interest and a prized acquisition in advanced collections of rare minerals and microminerals.

Properties

Mohs hardness
2
Luster
Vitreous
Streak
Light blue
Density
3.13
Cleavage
Perfect on {010}
Transparency
Transparent to translucent
Crystal system
Triclinic

Diagnostic features

## Identification Characteristic features of goldquarryite include its light blue color, specific occurrence as radial aggregates of acicular crystals, and extreme rarity. A key diagnostic clue is its origin from the only known locality – the Gold Quarry mine in Nevada. ## Distinguishing from Similar Minerals Goldquarryite can be confused with other blue secondary minerals. It differs from wavellite by its more acicular crystal habit and the lack of the typical radial-fibrous internal structure of wavellite aggregates. Turquoise is much harder and usually opaque. Faustite, with which it is sometimes confused, usually has a greenish tint. Final identification requires advanced analytical methods, such as X-ray diffraction (XRD) or chemical microanalysis (EDS). ## Crystal Forms Crystals are acicular or thin, platy, grouped into radial, stellate, or spherical aggregates. Individual, well-formed crystals are virtually unheard of.

Geological environment

## Genesis Goldquarryite is a secondary mineral that formed in the oxidation zone of a sediment-hosted gold deposit. Its crystallization occurred as a result of the interaction of solutions rich in phosphorus, fluorine, copper, and cadmium with sedimentary rocks. The presence of cadmium, which is a rare element, determines the uniqueness of this mineral. ## Mineral Associations This mineral occurs in association with other rare phosphates and sulfates, such as strengite, wavellite, wardite, minerals from the crandallite group (gorceixite, goyazite), faustite, and turquoise. ## Localities The only confirmed and described occurrence of goldquarryite in the world is its type locality – the Gold Quarry mine, Carlin Trend, Eureka County, Nevada, USA.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of goldquarryite specimens is primarily assessed based on the richness and aesthetics of the aggregates. Most prized are samples with well-defined, spherical or stellate clusters of intense blue color, contrasting with the rock matrix. The size of the aggregates and the presence of associated, well-formed accessory minerals also significantly increase the collectible value of the specimen. ## Popular Localities The only source of goldquarryite specimens is the Gold Quarry mine in Nevada. Minerals from this locality are highly sought after by collectors specializing in systematics and rare minerals.

Care and storage

## Cleaning Goldquarryite specimens are extremely delicate and fragile. For dust removal, it is best to use canned compressed air, applied from a safe distance. Wet cleaning should be avoided; if absolutely necessary, distilled water and a very soft brush can be used with utmost caution. ## What to Avoid The mineral is sensitive to chemicals, especially acids. It should be protected from high temperatures, which can cause dehydration and structural damage. Ultrasonic cleaners and any mechanical cleaning methods are not recommended. Direct sunlight should be avoided. ## Storage It is recommended to store specimens in sealed, padded "micromount" boxes, which protect them from dust, mechanical damage, and sudden changes in humidity. Display should be in stable conditions, away from heat sources and vibrations.

Sources

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