Aravaite

Chemical formula: Ba₂Ca₁₈(SiO₄)₆(PO₄)₃(CO₃)F₃O

Aravaite is an extremely rare mineral from the nabimusaite group, discovered in the Hatrurim Formation in Israel, distinguished by its complex chemical composition.

## Characteristics Aravaite is a mineral with an exceptionally complex chemical composition, belonging to the nabimusaite group. It occurs as very small, anhedral (lacking crystal faces) grains, typically not exceeding 20 micrometers in size. These grains are most commonly found as inclusions in other minerals, such as larnite or brownmillerite. Due to the microscopic size of its crystals, its visual characteristics cannot be assessed with the naked eye. ## Physical Properties Aravaite crystals are too small to allow for the macroscopic examination of standard physical properties such as hardness, density, luster, or transparency. The density was calculated based on the chemical formula and unit cell parameters, and is 3.25 g/cm³. Other properties remain unknown. ## Colors and Varieties Observed aravaite grains are colorless. No varieties have been distinguished. ## History and Name The mineral was officially recognized by the International Mineralogical Association (IMA) in 2012 under number 2012-064. Its name comes from the Arava (or Arawa) Valley, which is part of the Great African Rift and extends south of the Dead Sea, near the discovery site. It was described by a team of mineralogists: Evgeny V. Galuskin, Irina O. Galuskina, Yevgeny Vapnik, Biljana Lazic, and Joachim Kusz. ## Applications Aravaite, being an extremely rare mineral and occurring only in microscopic quantities, has no practical application. Its significance is purely scientific and collectible, although due to its size, it is not an object of interest for typical collectors.

Properties

Luster: Vitreous
Streak: White
Density: 3.25
Cleavage: None
Fracture: Uneven
Transparency: Transparent
Crystal system: Trigonal

Diagnostic features

## Identification Identification of aravaite is impossible without advanced laboratory techniques. It requires chemical analysis (e.g., using an electron microprobe - EDS/WDS) and structural studies (X-ray diffraction - XRD). In backscattered electron (BSE) images, it stands out from associated minerals (such as larnite) with a brighter shade, which results from the presence of the heavy element - barium. ## Distinguishing from Similar Minerals Distinguishing it from other minerals of the nabimusaite group (e.g., nabimusaite, dargaite) is possible only based on precise chemical analysis, particularly the content of barium, potassium, sodium, and calcium. ## Crystal Forms This mineral forms exclusively anhedral, i.e., lacking crystal faces, rounded grains up to 20 micrometers in size. They occur as inclusions in other minerals or fill spaces between them.

Geological environment

## Genesis Aravaite forms under pyrometamorphic conditions, i.e., contact metamorphism at very high temperatures, reaching 800-900°C, and low pressure. It is a product of natural cement clinker, formed by the combustion of underground bitumen deposits, which heated the surrounding sedimentary rocks (marls and limestones). ## Mineral Associations This mineral occurs in close association with other high-temperature minerals of the Hatrurim Formation. It is most commonly accompanied by: larnite, brownmillerite, mayenite, ye'elimite, as well as dargaite, nabimusaite, fluormayenite, fluorapatite, and maghemite. ## Localities The only confirmed locality of aravaite in the world is its type locality - the Hatrurim Formation in the Dead Sea basin in the Negev Desert, Israel.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of a specimen with aravaite is assessed solely based on the quality of the host rock and the richness of the mineral association. Aravaite itself is invisible to the naked eye, so its presence is of scientific value. Specimens with analytically confirmed presence of this mineral, especially in association with other rare minerals from this locality, are highly valued in specialized systematic and micromount collections. ## Popular Localities The only source of specimens is the Hatrurim Formation in Israel. Specimens from this locality are sought after by collectors specializing in rare minerals and minerals formed in pyrometamorphic processes.

Care and storage

## Cleaning Due to its microscopic nature of occurrence (mainly as inclusions in the host rock), individual aravaite crystals are not subject to cleaning. The host rock specimen can be cleaned mechanically, using a soft brush and distilled water. ## What to Avoid Contact of the rock containing aravaite with strong acids should be avoided, as they could damage both the mineral itself and associated minerals. There is no detailed data on its sensitivity to temperature or light, but standard caution is recommended. ## Storage Rock specimens with aravaite should be stored under stable conditions, away from dust and moisture, preferably in sealed boxes or display cases. The label should precisely indicate the location of the microscopic grains, if known.

Sources

IMA Mineral List (CNMNC)