Housleyite

Chemical formula: Pb<sup>2+</sup><sub>6</sub>Cu<sup>2+</sup>Te<sup>6+</sup><sub>4</sub>O<sub>18</sub>(OH)<sub>2</sub>

Housleyite is a rare lead, copper, and tellurium oxide, forming aggregates of small, tabular crystals with an intense red color.

## Characteristics Housleyite is an oxide mineral from the tellurate group, characterized by a complex chemical composition containing lead, copper, and tellurium. It occurs as very small, tabular or bladed crystals, rarely exceeding 0.2 mm in length. These crystals form rosette-like or random aggregates on the surface of the host rock. Its most distinctive visual feature is its intense, deep red or reddish-orange color. ## Physical Properties Housleyite crystals exhibit a vitreous to slightly adamantine luster. They are transparent to translucent. Due to the extremely small size of the crystals, hardness has not been precisely measured, but it is estimated to be low, in the range of 2-3 on the Mohs scale. This mineral is also very brittle. ## Colors and Varieties This mineral is monochromatic and does not form varieties. Its color is constant and ranges from deep red to reddish-orange. The streak is light red. ## History and Name The name housleyite was given in honor of Dr. Robert M. Housley (born 1936), a researcher from the California Institute of Technology. He was honored for his significant contributions to tellurium mineralogy, including his research on minerals from the Baker deposit in California, where housleyite was first identified. The mineral was officially recognized by the International Mineralogical Association (IMA) in 2010 (IMA2010-066). ## Uses Due to its extreme rarity and microscopic crystal size, housleyite has no industrial or commercial applications. It is solely an object of scientific and collector interest for specialists in rare minerals.

Properties

Mohs hardness
2-3
Luster
Vitreous to Subadamantine
Streak
Light red
Cleavage
Perfect on {0001}
Fracture
Brittle
Transparency
Transparent to translucent
Crystal system
Trigonal

Diagnostic features

## Identification Field identification of housleyite is practically impossible due to its microscopic size. In a collection, it can be recognized by its characteristic, intense red color, tabular crystal habit forming rosette aggregates, and co-occurrence with other rare tellurates and tellurides. Definitive identification requires advanced analytical methods, such as Raman spectroscopy or EDS analysis. ## Differentiation from Similar Minerals It can be confused with other red secondary tellurium minerals, such as kuranakhite, ottoite, or some forms of emmonsite. Differentiating it from these based on visual characteristics is very difficult and usually requires chemical analysis. However, housleyite is distinguished by its specific, tabular crystal morphology. ## Crystal Forms It forms very small, thin, tabular crystals with a hexagonal or octagonal outline. These crystals often combine into rosette-like or irregular aggregates.

Geological environment

## Genesis Housleyite is a secondary mineral, formed in the oxidation (weathering) zones of ore deposits rich in tellurium. It forms as a result of the alteration of primary tellurides under low temperature and pressure conditions, in the presence of oxygen and surface waters. ## Mineral Associations In its type locality (Baker mine), housleyite co-occurs with many other rare tellurium minerals, such as: tellurite, paratellurite, emmonsite, mackayite, ottoite, leisingite, jensenite, as well as native gold, quartz, and barite. ## Localities The only confirmed occurrence of housleyite in the world is its type locality – the Baker mine, located in the Vulcan District, San Bernardino County, California, USA.

Rarity

Extremely rare

For collectors

## Quality Criteria For micromineral collectors, the most valuable specimens are those with clearly formed, undamaged crystals creating aesthetic, rosette-like aggregates. The intensity and purity of the red color are highly prized. Contrast with a light host rock (e.g., quartz) also enhances the specimen's attractiveness. The size of individual crystals, even if it's a difference of tenths of a millimeter, is significant. ## Popular Localities The only source of housleyite specimens is the Baker mine in California. Material from this historic locality is highly sought after by specialized collectors.

Care and storage

## Cleaning Housleyite specimens are extremely delicate and small. Mechanical or chemical cleaning is not recommended. If absolutely necessary, compressed air can be used from a safe distance to remove loose dust particles. Any contact with water or other liquids should be avoided. ## What to Avoid Contact with water, chemicals, ultrasound, and sudden temperature changes must be strictly avoided. The mineral is very brittle, so it should be protected from shocks and impacts. ## Storage Housleyite specimens should be stored in stable conditions, in closed, transparent "micromount" boxes that protect them from dust, moisture, and mechanical damage. Exposure to direct sunlight should be avoided, although there is no evidence of fading.

Sources

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