Wortupaite

Chemical formula: MgNi₂+₂(Te₄+O₃)₃·₃H₂O

Wortupaite is an extremely rare magnesium nickel tellurite, forming microscopic, hexagonal crystals of an intense green color.

## Characteristics Wortupaite is a hydrated magnesium nickel tellurite, occurring as extremely small, hexagonal crystals. It typically forms prismatic or tabular crystals not exceeding 0.2 mm in size, which aggregate into rosettes or appear as single, overgrown crystals. Its intense, emerald-green color makes it distinctive, despite its microscopic scale. ## Physical Properties Wortupaite crystals exhibit a vitreous luster. Due to the small size of the crystals, many physical properties, such as hardness or density, have not been precisely measured. The density was calculated based on the formula and unit cell parameters and is approximately 4.05 g/cm³. ## Colors and Varieties This mineral is characterized by a uniform, vivid, emerald-green color. No color varieties or commercial forms are known. ## History and Name The mineral's name comes from its discovery locality – the Worturpa mine in the Flinders Ranges, South Australia. It was described and approved as a new mineral species by the International Mineralogical Association (IMA) in 2009 (IMA2009-064). The discovery was made by a team of mineralogists, including P. Elliott, who authored the description of many new minerals from this region. ## Uses Wortupaite has no industrial applications. Its significance is purely scientific and as a collector's item, being a coveted object for specialized collectors of rare minerals (so-called "micromounts").

Properties

Luster: Vitreous
Streak: Light green
Density: 4.05
Cleavage: None
Fracture: Uneven
Transparency: Transparent to translucent
Crystal system: Hexagonal

Diagnostic features

## Identification Identifying wortupaite in the field is practically impossible due to its microscopic size. In a collection, it is recognized by its characteristic emerald-green color, hexagonal crystal outline, and typical occurrence as rosette aggregates. Association with the type locality (Worturpa mine) and co-occurring minerals is crucial. ## Distinguishing from Similar Minerals Wortupaite can be confused with other secondary, green nickel minerals, such as nickellineite or ahlfeldite, which may also occur in the same locality. Definitive differentiation requires advanced analytical methods, such as Raman spectroscopy or chemical analysis using an electron microprobe (EDS/WDS). ## Crystal Forms Wortupaite crystallizes in hexagonal, prismatic, or tabular forms. It often forms radial or rosette aggregates, where individual crystals radiate from a common center.

Geological environment

## Genesis Wortupaite is a secondary mineral, formed in the oxidation zones (gossans) of ore deposits containing tellurium. It forms as a result of the weathering of primary tellurides in an environment rich in nickel and magnesium. Its formation is associated with strongly alkaline conditions prevailing within dolomitic rocks. ## Mineral Associations This mineral co-occurs with other rare tellurites and tellurates. At the type locality, it has been found in association with quartz, magnesite, and other tellurium minerals such as paratellurite, cliffordite, ahlfeldite, nickellineite, and juabite. ## Localities The only confirmed occurrence of wortupaite in the world is its type locality: the Worturpa mine, located in the northern Flinders Ranges, South Australia.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of wortupaite specimens is primarily assessed based on the richness and aesthetics of the crystal aggregates. Most valued are specimens with numerous, well-formed, and undamaged crystal rosettes, clearly contrasting with the matrix rock. The intensity of the emerald-green color also contributes to the specimen's attractiveness. Due to its microscopic nature, the quality of the "micromount" itself is key. ## Popular Localities All known collector specimens originate from a single location worldwide – the Worturpa mine in South Australia. It is an endemic mineral to this locality.

Care and storage

## Cleaning Wortupaite specimens are extremely delicate and small. Mechanical cleaning is inadvisable and can lead to crystal damage. If absolutely necessary, compressed air can be used from a safe distance to remove dust. Avoid contact with water and any chemicals. ## What to Avoid Absolutely avoid contact with water, acids, bases, and other solvents. The crystals are brittle and sensitive to shocks and temperature changes. Do not expose specimens to direct sunlight, which can cause fading or degradation. ## Storage Wortupaite specimens should be stored exclusively in specialized micromount boxes, which protect them from dust, humidity, and mechanical damage. Store in stable conditions, away from heat and light sources.

Sources

IMA Mineral List (CNMNC)