Rajite

Chemical formula: Cu₂+Te₄+₂O₅

Rajite is a very rare copper tellurite, forming aggregates of small, platy crystals with a characteristic golden-brown color.

## Characteristics Rajite is an oxide mineral, specifically a copper tellurite. It occurs as aggregates of very small, platy or acicular crystals, rarely exceeding 1 mm in length. Its most characteristic features are its golden-brown to brown color and vitreous luster. It is a secondary mineral, forming in the oxidation zones of ore deposits. ## Physical Properties Rajite crystals are brittle. The mineral has a hardness of approximately 2 on the Mohs scale. It has a relatively high density, around 5.96 g/cm³, which is typical for minerals containing heavy elements like tellurium. It is transparent to translucent. ## Colors and Varieties Rajite occurs in uniform colors, ranging from golden-brown, through reddish-brown, to brown. No distinct color varieties or commercial varieties are recognized. ## History and Name The mineral was discovered in the dumps of the Lone Pine mine in the Wilcox area, Cochise County, Arizona (USA). It was described in 1980 by William W. Pinch and Sidney A. Williams. The name "rajite" honors Robert A. Jenkins (born 1941), an American chemist and mineral collector from Arizona, who first found and drew attention to this mineral. ## Uses Rajite has no industrial applications. Its significance is purely scientific and as a collector's item, as a very rare and well-defined mineral species.

Properties

Mohs hardness: 2
Luster: Vitreous
Streak: Light brown
Density: 5.96
Cleavage: Good on {100}
Fracture: Uneven
Transparency: Transparent to translucent
Crystal system: Monoclinic

Diagnostic features

## Identification Rajite can be identified by its characteristic golden-brown color, vitreous luster, and form of small, platy crystals. The key is its occurrence – it forms in the oxidation zones of tellurium deposits, often in association with other rare tellurites and tellurates. ## Distinguishing from similar minerals It can be confused with other rare, brown copper tellurites, such as teineite or poughite. Definitive differentiation requires advanced analytical methods, such as X-ray diffraction (XRD) or chemical analysis (EDS), due to visual similarity and co-occurrence. ## Crystal forms It forms elongated, platy crystals, often flattened, with a rectangular cross-section. These crystals group into radial or chaotic aggregates, growing on the host rock, often in small vugs and fissures.

Geological environment

## Genesis Rajite is a secondary mineral that forms as a result of oxidation (weathering) processes of primary tellurium and copper minerals under low temperature and pressure conditions. It forms within the oxidation zones (so-called gossans) of ore deposits, usually in arid climates. ## Mineral associations It most commonly co-occurs with other secondary tellurium minerals, such as teineite, poughite, parakhinite, dugganite, xocomecatlite, as well as with quartz, barite, and minerals from the iron hydroxide group (e.g., goethite). ## Localities The most important and type locality for rajite is the Lone Pine mine in Arizona, USA, from which the best-known specimens originate. It has also been identified in the El Plomo mine in Honduras and the Wendy mine in La Paz County, also in Arizona.

Rarity

Very rare

For collectors

## Quality criteria The most highly prized rajite specimens are those that possess rich aggregates of well-formed, lustrous crystals with an intense, golden-brown color. Contrast with a light host rock (most often quartz) and the presence of rare associated minerals are also important. Due to the small size of the crystals, specimens are primarily evaluated under a microscope. ## Popular localities The only source of collector-quality specimens is the type locality – the Lone Pine mine in Arizona, USA. Specimens from other locations are extremely rare and are primarily of scientific importance.

Care and storage

## Cleaning Rajite specimens should be cleaned with utmost care, using only compressed air to remove dust. Due to its extreme brittleness and small crystal size, any mechanical contact, including with brushes or water, should be avoided. ## What to avoid Contact with water, chemical agents, and especially acids, must be strictly avoided. The mineral is very brittle, so it should be protected from vibrations, impacts, and sudden temperature changes. ## Storage Rajite specimens are best stored in sealed, padded "micromount" boxes to protect them from dust and mechanical damage. It is not sensitive to light, but storage in stable room conditions is recommended.

Sources

IMA Mineral List (CNMNC)