Ferribushmakinite

Chemical formula: Pb<sup>2+</sup><sub>2</sub>Fe<sup>3+</sup>(PO<sub>4</sub>)(V<sup>5+</sup>O<sub>4</sub>)(OH)

Ferribushmakinite is a rare secondary mineral of the brackebuschite group, being the iron (Fe³⁺) analog of bushmakinite.

## Characteristics Ferribushmakinite is a rare mineral from the phosphate class, belonging to the apatite supergroup and the brackebuschite group. It occurs as very small, bladed or prismatic crystals, which usually form radial aggregates, rosettes, or spherulites. Individual crystals rarely exceed 0.2 mm in length. Due to the small size of the crystals, its macroscopic features are difficult to observe without magnification. ## Physical Properties The crystals exhibit a luster described as resinous to greasy. The mineral is translucent. Due to the small size of the crystals and its rarity, properties such as hardness, density, or cleavage have not been precisely determined, although the Mohs hardness is estimated to be around 4-5. ## Colors and Varieties Ferribushmakinite has a characteristic, bright color ranging from yellowish-green to greenish-yellow. The streak of the mineral is light yellow. No varieties are distinguished. ## History and Name The mineral was first described in 2002 by S. J. Mills, A. J. Criddle, C. J. Stanley, and G. Kolitsch. Its name refers to its chemical composition – it is an analog of bushmakinite, in which bismuth (Bi³⁺) has been replaced by iron (Fe³⁺). The name bushmakinite, in turn, comes from the name of the Russian mineralogist Anatoliy F. Bushmakin. The type locality (locus typicus) is the Kintore Opencut mine in Broken Hill, New South Wales (Australia). ## Uses Ferribushmakinite has no industrial application. It is solely an object of scientific and collecting interest, sought after by collectors specializing in rare minerals or phosphate minerals.

Properties

Mohs hardness
4-5
Luster
Resinous to greasy
Streak
Light yellow
Cleavage
Good on {100}
Fracture
Uneven
Transparency
Translucent
Crystal system
Monoclinic

Diagnostic features

## Identification Identification of ferribushmakinite is based on its characteristic, bright, yellowish-green color, radial or spherulitic aggregates, and co-occurrence with other secondary lead minerals and phosphates. Due to the small crystal size, definitive identification requires advanced analytical methods such as Raman spectroscopy or chemical analysis (EDS). ## Distinguishing from Similar Minerals Ferribushmakinite can be confused with other minerals from the brackebuschite group, such as bushmakinite (Bi-analog) or arsenbrackebuschite (with As instead of P). Visually, it is almost identical to pyromorphite, with which it often co-occurs; however, pyromorphite usually forms better-developed, hexagonal crystals. Distinguishing it from these minerals without specialized equipment is practically impossible. ## Crystal Forms The mineral forms very small, bladed crystals, elongated along the [010] axis and flattened on {100}. These crystals combine into radial aggregates, rosettes, and spherulitic forms, growing on other minerals.

Geological environment

## Genesis Ferribushmakinite is a secondary mineral, forming in the oxidation zones (iron gossan) of polymetallic deposits rich in lead, vanadium, and phosphorus. It forms as a result of the weathering of primary ore minerals in the presence of solutions containing phosphate and vanadate ions. ## Mineral Associations This mineral co-occurs with other secondary phosphate and vanadate minerals. It is most commonly found in association with pyromorphite, corkite, hinsdalite, plumbogummite, apatite, goethite, and quartz. ## Localities The most important and type locality for ferribushmakinite is the Kintore Opencut mine in Broken Hill, New South Wales, Australia. This is the only confirmed and well-documented locality for this mineral worldwide.

Rarity

Very rare

For collectors

## Quality Criteria The quality of a ferribushmakinite specimen is primarily assessed based on the richness and aesthetics of its aggregates. The most desirable specimens are those with well-formed, distinct rosettes or spherulites of intense, yellowish-green color, contrasting with the rock matrix. The size of the aggregates, although always microscopic, is also important – larger and denser clusters are more highly valued. The absence of damage to the delicate crystals is also crucial. ## Popular Localities The only source of collectible specimens is the historic locality in Broken Hill, Australia. Specimens from this locality are highly prized by collectors specializing in rare minerals (so-called "micromounts") and systematic minerals.

Care and storage

## Cleaning Due to its extreme rarity and small crystal size, ferribushmakinite specimens are typically not cleaned. If absolutely necessary, compressed air can be used to remove dust. Contact with water and chemicals should be avoided. ## What to Avoid Avoid contact with all liquids, acids, and bases. The crystals are very small and fragile, so vibrations, impacts, and abrasion should be avoided. It should not be subjected to ultrasonic cleaning. Protect from high temperatures. ## Storage Ferribushmakinite specimens should be stored under stable conditions, in a closed "micromount" box, to protect them from dust and mechanical damage. Exposure to direct sunlight should be avoided, although there is no evidence of fading.

Sources

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