Gazeevite

Chemical formula: BaCa₆(SiO₄)₂(S₆+O₄)₂O

Gazeevite is a very rare mineral from the silicate group, discovered in Jordan, distinguished by its unique chemical composition containing barium, calcium, silicon, and sulfur.

## Characteristics Gazeevite is an extremely rare mineral that was officially recognized by the International Mineralogical Association (IMA) in 2013. It occurs as very fine, anhedral (lacking crystal faces) grains, usually not exceeding 100 micrometers in size. These grains are most often intergrown with other minerals. Due to the microscopic size of the crystals, visual characteristics visible to the naked eye are unknown. ## Physical Properties The mineral is transparent to translucent, with a white streak and vitreous luster. Its Mohs hardness is 5, and its density, calculated based on the chemical formula and unit cell parameters, is 3.83 g/cm³. Neither cleavage nor fluorescence in ultraviolet light has been observed. ## Colors and Varieties Observed gazeevite grains are colorless. No colored varieties are known. ## History and Name The mineral's name honors Professor Victor Gazeev from the Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry of the Russian Academy of Sciences in Moscow, in recognition of his contribution to the study of rocks from the Hatrurim Formation. It was discovered in samples from the Daba-Siwaqa area in Jordan, which is the type locality for this mineral. ## Applications Gazeevite has no industrial applications. Its significance is purely scientific and collector-oriented, as a unique and extremely rare component of a specific geological formation.

Properties

Mohs hardness: 5
Luster: Vitreous
Streak: White
Density: 3.83
Cleavage: None
Fracture: Uneven
Transparency: Transparent to translucent
Crystal system: Trigonal

Diagnostic features

## Identification Identification of gazeevite is impossible without advanced laboratory techniques. This requires chemical analysis (e.g., using an electron microprobe - EDS/WDS) and structural studies (X-ray diffraction - XRD). Under collecting and field conditions, it is unrecognizable. It occurs as colorless, microscopic grains within the rock. ## Distinguishing from Similar Minerals Due to its unique chemical composition, after analysis, it is easy to distinguish from other minerals. Visually, its microscopic grains can be mistaken for many other colorless rock-forming minerals, such as quartz or calcite, but it differs completely from them in terms of chemical and structural properties. ## Crystal Forms Gazeevite forms exclusively anhedral, irregular grains up to 100 µm in size, occurring within the host rock. No well-formed (euhedral) crystals have been observed.

Geological environment

## Genesis Gazeevite forms under unique conditions of pyrometamorphic (contact) metamorphism at high temperature and low pressure. It is a product of the combustion and recrystallization of a protolith – marly and calcareous sediments. This process occurs in the Hatrurim Formation (also known as the "Mottled Zone"), which is known for the occurrence of rare minerals formed by natural ignition and combustion of bitumens contained in the rocks. ## Mineral Associations This mineral coexists with other rare pyrometamorphic products of the Hatrurim Formation. It is most commonly associated with larnite, brownmillerite, mayenite, as well as newly discovered minerals such as nabimusaite and dargaite. It also occurs with calcite and sulfates. ## Localities The only confirmed locality of gazeevite in the world is its type locality: the Daba-Siwaqa area in the Hatrurim complex, near Amman in Jordan.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of a gazeevite specimen is determined solely by its scientific and documentary value. Since the mineral is microscopic, specimens do not possess aesthetic qualities in the traditional sense. The most valuable samples are those in which the presence of gazeevite has been analytically confirmed (so-called "cotype" or material from the type locality). The richness of associated minerals from the Hatrurim Formation can enhance the attractiveness of a specimen for specialized collectors. ## Popular Localities The only source of specimens is the type locality in Jordan. Material from this location is extremely difficult to acquire and appears on the collector's market sporadically, mainly within academic circles or among specialized dealers.

Care and storage

## Cleaning Specimens containing gazeevite, due to the microscopic size of the grains and their occurrence within the host rock, generally do not require and should not undergo cleaning. Any mechanical or chemical intervention can destroy the delicate mineral grains. If necessary, dust can be removed using compressed air or a very soft brush. ## What to Avoid Contact with chemicals, acids, and ultrasonic cleaners should be strictly avoided. The host rock may be sensitive to changes in temperature and humidity. Specimens should be protected from direct sunlight, which can affect associated minerals. ## Storage Specimens should be stored in stable conditions, in closed boxes or display cases, to protect them from dust and mechanical damage. Storage in a dry place, away from heat sources and direct light, is recommended.

Sources

IMA Mineral List (CNMNC)