Midbarite

Chemical formula: Ca₃Mg₂(V₅+₂Si)O₁₂

Midbarite is an extremely rare mineral of the garnet group, a calcium, magnesium, and vanadium silicate, discovered in the Negev Desert in Israel.

## Characteristics Midbarite is a mineral belonging to the garnet supergroup. It occurs as very small, single, rounded grains, usually not exceeding 50 micrometers in size. Due to its extreme rarity and microscopic crystal size, its visual characteristics are not well understood from macroscopic specimens. ## Physical Properties As a member of the garnet group, midbarite is characterized by high hardness, estimated at approximately 7 on the Mohs scale. It has a vitreous luster and is transparent. Its density, calculated based on the formula and unit cell parameters, is 3.75 g/cm³. ## Colors and Varieties The observed midbarite grains are colorless. No colored varieties are known. ## History and Name The mineral was first described in 2013 by Irina O. Galuskina and co-workers. Its name comes from the Hebrew word "midbar" (מדבר), meaning desert, which refers to its discovery location – the Hatrurim Formation in the Negev Desert, Israel. It was approved by the International Mineralogical Association (IMA) under number 2013-011. ## Uses Midbarite has no industrial application. Its significance is purely scientific and collectible, as a unique member of the garnet group.

Properties

Mohs hardness: 7
Luster: Vitreous
Streak: White
Density: 3.75
Cleavage: None
Fracture: Conchoidal
Transparency: Transparent
Crystal system: Cubic

Diagnostic features

## Identification Identification of midbarite is possible only using advanced laboratory techniques, such as X-ray microanalysis (EDS/WDS) in conjunction with scanning electron microscopy (SEM) or electron backscatter diffraction (EBSD). Optical identification at a macroscopic scale or even under a standard microscope is impossible. ## Distinguishing from Similar Minerals Midbarite is isostructural with other garnets. Distinguishing it from other colorless garnets, such as grossular or pyrope, requires precise chemical analysis, particularly confirming the dominance of vanadium and silicon at a specific position in the crystal structure. ## Crystal Forms This mineral forms only microscopic, rounded grains up to 50 μm in size. Well-formed, isometric crystals typical of garnets have not been observed.

Geological environment

## Genesis Midbarite forms under pyrometamorphic conditions, i.e., rock transformations under very high temperature and low pressure. It occurs in calc-silicate rocks of the Hatrurim Formation, which were burned as a result of natural fires of underground bitumen deposits. ## Mineral Associations This mineral co-occurs with other rare minerals formed under similar conditions, such as larnite, brownmillerite, ye'elimite, as well as calcite and other calcium silicates. ## Localities The only confirmed locality of midbarite in the world is its type locality: the Hatrurim Formation, near Har Parsa in the Negev Desert, Israel.

Rarity

Extremely rare

For collectors

## Quality Criteria As a "micromount" type mineral, the collectible value of a midbarite specimen depends on its presence being confirmed by a reliable laboratory. The richness of the mineral association on a given rock fragment and the clarity and size (on a micro scale) of the midbarite grains enhance its attractiveness. These specimens are valued exclusively in specialized collections of rare minerals and microminerals. ## Popular Localities The only source of specimens is the type locality in Israel. Material from this location is extremely difficult to obtain and is available only in scientific circles or on a highly specialized collector's market.

Care and storage

## Cleaning Due to the microscopic size of the grains and their occurrence within the host rock, cleaning individual crystals is practically impossible and unnecessary. Rock specimens containing midbarite should be handled with the utmost care. ## What to Avoid All chemical, ultrasonic, and mechanical cleaning methods that could damage or destroy the microscopic mineral grains embedded in the rock should be avoided. The host rock should be protected from acids and sudden temperature changes. ## Storage Specimens containing midbarite should be stored under stable conditions, in specialized "micromount" boxes, protecting them from dust, moisture, and mechanical damage. Identification of grains requires the use of a microscope, so precise marking of the mineral's location on the specimen is important.

Sources

IMA Mineral List (CNMNC)