AlSO4(OH)

Chemical formula: AlSO<sub>4</sub>(OH)

A rare, secondary aluminum sulfate, forming colorless or white fibrous coatings and crusts in acidic mine environments.

## Characteristics Jurbanite is a hydrated aluminum hydroxy-sulfate, most commonly found as delicate, fibrous aggregates, silky coatings, or crusts. It rarely forms acicular or hair-like crystals visible to the naked eye. It is a colorless or white mineral. ## Physical Properties This mineral is very soft and brittle. It has a vitreous luster, and in the case of fibrous aggregates, a silky luster. It is transparent to translucent. Its density is low, approximately 1.9 g/cm³. ## Colors and Varieties Jurbanite is typically colorless or white. No colored varieties or trade names are distinguished for it. ## History and Name It was first described in 1976. Its name comes from Joseph J. Urban (1915-1997), an American mineral collector who collected the first samples of this mineral at the San Manuel mine in Arizona, USA. ## Uses Due to its rarity, instability, and small crystal size, jurbanite has no industrial applications. It is of scientific and collector's interest only.

Properties

Luster
Vitreous, Silky
Streak
White
Density
1.89-1.91
Cleavage
Perfect on {100}
Transparency
Transparent to Translucent
Crystal system
Monoclinic

Diagnostic features

## Identification Key features include its occurrence environment (mine coatings), fibrous or acicular appearance, white color, and silky luster. Reaction to water (solubility) is a diagnostic feature, but it destroys the specimen. ## Distinguishing from similar minerals It can be confused with other secondary sulfates such as gypsum, epsomite, alunogen, or halotrichite. Gypsum is much more common and is not as readily soluble in cold water. Accurate identification usually requires chemical or X-ray diffraction (XRD) analysis. ## Crystal Forms It forms acicular or hair-like crystals, often gathered in radial or tangled aggregates. Most commonly found as crusts and coatings with a fibrous structure.

Geological environment

## Genesis It is a secondary mineral, formed by weathering processes in the oxidation zones of sulfide deposits. It crystallizes from acidic mine waters, rich in aluminum and sulfates, under low-temperature conditions. ## Mineral Associations It often occurs in association with other secondary sulfates, such as gypsum, epsomite, alunite, alunogen, and also with iron oxides (goethite). ## Localities The most important locality in the world is the San Manuel mine in Arizona (USA), where it was discovered. It is also found in other copper mines in Arizona, in Chuquicamata in Chile, and in some mines in Germany.

Rarity

Very rare

For collectors

## Quality Criteria For collectors, the abundance and quality of crystal formation are most important – the longer and better-formed the needles, the more valuable the specimen. Association with other minerals and accurate locality documentation are also important. ## Popular Localities The most prized specimens come from the type locality – the San Manuel mine in Arizona, USA.

Care and storage

## Cleaning **Absolutely do not clean jurbanite with water or any liquids**, as it is soluble in them. Contaminants can only be removed mechanically, using a soft brush or carefully blowing with compressed air from a safe distance. ## What to avoid Avoid contact with water and high humidity, which can lead to its dissolution or alteration into other minerals. It is a very delicate mineral, sensitive to shock and touch. ## Storage Jurbanite specimens should be stored in a dry place, preferably in tightly sealed boxes ("membrane box" type) or containers with a desiccant (e.g., silica gel).

Sources

Read more