Wicksite

Chemical formula: NaCa<sub>2</sub>Fe<sup>2+</sup><sub>2</sub>(Fe<sup>3+</sup>,Mn<sup>2+</sup>,Fe<sup>2+</sup>)<sub>4</sub>(PO<sub>4</sub>)<sub>6</sub>·2H<sub>2</sub>O

Wicksite is a very rare, black phosphate mineral, forming characteristic, tabular crystals aggregated into rosettes.

## Characteristics Wicksite is a complex, hydrated sodium, calcium, iron, and manganese phosphate. It most often forms small, black, opaque, tabular crystals. These tend to grow together into groups and aggregates resembling rosettes, which is very characteristic of this mineral. Less frequently, it occurs as granular aggregates. The luster can be vitreous, and on some surfaces, approaching subadamantine. ## Physical Properties The hardness of wicksite on the Mohs scale is 4.5 to 5, classifying it as a mineral of medium hardness. Its density is approximately 3.54 g/cm³. It is brittle and opaque. The streak, which is the color of the powdered mineral, is greenish-gray. ## Colors and Varieties This mineral is monochromatic – it occurs exclusively in black. No color or commercial varieties are distinguished. ## History and Name Wicksite was first described in 1981 by B. D. Sturman, Donald R. Peacor, and Pete J. Dunn. The mineral is named in honor of Frederick John Wicks (born 1937), curator of mineralogy at the Royal Ontario Museum in Toronto, in recognition of his contributions to the study of phosphate minerals. The type locality, from which the first described specimens originated, is the Big Fish River area in the Dawson District of Canada's Yukon Territory. ## Applications Wicksite has no industrial applications. It is a mineral of purely scientific and collector's interest, sought after for its rarity and aesthetic crystalline forms.

Properties

Mohs hardness
4.5-5
Luster
Vitreous to Sub-Adamantine
Streak
Greenish-gray
Density
3.54
Cleavage
Good on {010}
Fracture
Uneven
Transparency
Opaque
Crystal system
Orthorhombic

Diagnostic features

## Identification Key diagnostic features of wicksite are its black color, characteristic habit of thin tabular crystals forming rosette-like aggregates, and vitreous to subadamantine luster. The greenish-gray streak is also helpful in identification. The origin locality (Yukon, Canada) is a very strong indicator. ## Distinguishing from Similar Minerals Wicksite can be confused with other black minerals found in the same environment, such as maricite. However, maricite usually forms granular or spherical aggregates, not tabular rosettes. Final distinction from other rare, black phosphates from this locality may require advanced studies, such as chemical analysis. ## Crystal Forms Wicksite crystallizes in the orthorhombic system. The most common form consists of thin, tabular crystals, which often arrange themselves into fan-shaped or radial aggregates, forming striking rosettes. It also occurs as granular aggregates within the rock mass.

Geological environment

## Genesis Wicksite is a secondary mineral, forming within siderite iron formations. It forms in the late stage of hydrothermal processes or low-grade metamorphism, filling fractures and rock cavities or crystallizing within concretions. ## Mineral Associations This mineral occurs in association with other, often rare, phosphates. The most common associated minerals include wolfeite, satterlyite, maricite, pyrite, and quartz. ## Localities The most important and practically sole source of well-formed, collectible wicksite specimens is the area along the Big Fish River and Rapid Creek in the Dawson District, Yukon Territory, Canada. This is a world-renowned locality for rare phosphate minerals.

Rarity

Very rare

For collectors

## Quality Criteria The most highly prized wicksite specimens are those with sharply defined, lustrous crystals formed into distinct, aesthetic rosettes. The larger and better-defined the crystals, the higher the value of the specimen. Contrast with a light matrix rock and the presence of other rare associated minerals also enhance collector appeal. ## Popular Localities The vast majority, if not all, wicksite specimens available on the collector's market come from a single location in the world: the Big Fish River / Rapid Creek area in Yukon, Canada. Specimens from this locality are considered classics and benchmarks for this species.

Care and storage

## Cleaning Wicksite specimens should be cleaned very carefully, using a soft brush to remove dust. If necessary, it can be rinsed with distilled water. Ultrasonic cleaners should be avoided, as they can damage the brittle crystals. ## What to Avoid The mineral is sensitive to acids and strong chemicals. It should be protected from impacts and scratching by harder minerals. There are no specific recommendations regarding light or temperature exposure, but it is advisable to avoid extreme conditions. ## Storage It is recommended to store wicksite specimens in separate, sealed collector boxes to protect them from dust and mechanical damage. Display should provide stable conditions and protection from direct contact with other minerals.

External references

Sources

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