Höslite
Chemical formula: Fe<sup>3+</sup><sub>3</sub>(VO<sub>4</sub>)<sub>2</sub>(SO<sub>4</sub>)(OH)(H<sub>2</sub>O)<sub>4</sub>·3H<sub>2</sub>O
Höslite is a very rare, hydrated iron sulfate and vanadate, forming microscopic, tabular crystals of an orange-red color.
Properties
- Luster
- Vitreous
- Streak
- Light yellow
- Density
- 2.64
- Cleavage
- Perfect on {010}
- Fracture
- Uneven
- Transparency
- Transparent to translucent
- Crystal system
- Monoclinic
Diagnostic features
## Identification Identification of höslite is possible almost exclusively using advanced analytical methods, such as Raman spectroscopy or X-ray diffraction (XRD), due to its microscopic size. Visually, under high magnification, it can be identified by its characteristic orange-red color, tabular crystal habit, and specific, rosetted growth pattern. Its occurrence in paragenesis with other secondary vanadates in the oxidation zone of uranium deposits is a key indicator. ## Distinguishing from Similar Minerals Höslite can be confused with other secondary, orange or red vanadium minerals, such as carnotite or tyuyamunite, but it differs from them in crystal habit (thin tablets) and chemical composition (presence of the sulfate group). Definitive differentiation requires laboratory analysis. ## Crystal Forms Höslite crystallizes as very thin, tabular crystals with a rectangular or bladed outline. These crystals often form radial or rosetted aggregates, and also occur as single, scattered flakes on the surface of the host rock.
Geological environment
## Genesis Höslite is a secondary mineral, forming in the oxidation zones of polymetallic deposits, particularly uranium deposits, in arid or semi-arid climates. It forms as a result of the weathering of primary minerals containing vanadium, iron, and sulfides. At the type locality (Strelley mine), it formed in voids within weathered quartz sandstone. ## Mineral Associations This mineral co-occurs with other rare secondary minerals. At its type locality in Australia, it has been found in association with quartz, hematite, gypsum, jarosite, carnotite, metatyuyamunite, strelleyite, as well as newly described minerals such as heneganyite and mundrabillite. ## Localities The only confirmed and described occurrence of höslite in the world is its type locality: the Strelley uranium mine, located in the Pilbara region of Western Australia.
Rarity
Extremely rare
For collectors
## Quality Criteria As a micromount mineral, the collector's value of höslite depends on several factors. The most highly prized specimens are those showing well-formed, sharp, and undamaged crystal aggregates, preferably in the form of aesthetic rosettes. The contrast with the host rock matrix and the abundance of crystals on the sample surface are also important. The presence of other rare associated minerals, especially those from the type locality, significantly increases the specimen's value. ## Popular Localities The only source of höslite specimens is its type locality - the Strelley mine in Western Australia. All specimens available on the collector's market originate from this single location.
Care and storage
## Cleaning Specimens with höslite should be handled with the utmost care. Due to the microscopic size and brittleness of the crystals, mechanical cleaning is not recommended. If absolutely necessary, compressed air can be used from a safe distance to remove loose dust. Contact with water and any chemicals should be avoided. ## What to Avoid Contact with water, acids, bases, and other solvents, which can damage or completely dissolve the microscopic crystals, must be strictly avoided. The mineral is likely sensitive to high temperatures and humidity changes. ## Storage Höslite specimens should be stored under stable conditions, in closed, airtight "micromount" containers that protect them from dust, mechanical damage, and humidity fluctuations. Exposure to direct sunlight and vibrations should be avoided.