Shulamitite

Chemical formula: Ca₃Ti⁴⁺Fe³⁺AlO₈

Shulamite is a rare mineral of the brownmillerite group, a calcium, titanium, iron, and aluminum oxide, discovered in the Hatrurim Formation in Israel.

## Characteristics Shulamite is a rare mineral belonging to the brownmillerite subgroup. It occurs as very small, tabular or platy crystals, usually not exceeding 20 micrometers in size, which form aggregates and clusters. It is opaque and has a reddish-brown color. ## Physical Properties This mineral is characterized by a hardness ranging from 6-7 on the Mohs scale, making it relatively hard. Its density is approximately 3.84 g/cm³. It possesses a luster described as metallic to submetallic. It exhibits good cleavage in one direction and imperfect cleavage in two others. ## Colors and Varieties Shulamite occurs in a uniform, reddish-brown color. No color varieties or commercial varieties are known. ## History and Name The mineral was officially described and approved by the International Mineralogical Association (IMA) in 2011. Its name comes from the first name Shulamit, in honor of the Israeli geologist Shulamit Gross (1923–2012), who dedicated her career to studying the unique geology of the Hatrurim Formation, where this mineral was discovered. ## Applications Due to its extreme rarity and microscopic crystal sizes, shulamite has no industrial applications. It is of purely scientific significance and is an object of interest for specialized micromineral collectors.

Properties

Mohs hardness
6-7
Luster
Metallic to submetallic
Streak
Light brown
Density
3.84
Cleavage
Good on {010} and imperfect on {001} and {100}
Fracture
Irregular/Uneven
Transparency
Opaque
Crystal system
Orthorhombic

Diagnostic features

## Identification Identification of shulamite is impossible without advanced laboratory techniques, such as X-ray microanalysis (EDS/WDS) and X-ray diffraction (XRD). In collector conditions, identification relies on a label from a confirmed locality. A characteristic feature is its occurrence in the specific geological environment of the Hatrurim Formation. ## Distinguishing from Similar Minerals It can be confused with other oxides of similar composition and appearance, such as lakargiite or other minerals from the perovskite and brownmillerite groups, which co-occur in the same locality. Definitive distinction requires chemical analysis to determine the proportions of titanium, iron, and aluminum. ## Crystal Forms Shulamite crystals are very small, typically less than 20 µm in size. They adopt a tabular or platy form and create irregular aggregates with other minerals.

Geological environment

## Genesis Shulamite forms under unique conditions of pyrometamorphic (contact) metamorphism at high temperatures and low pressure. Its formation is associated with processes occurring in the carbonate-silicate rocks of the Hatrurim Formation, which underwent natural burning due to the combustion of underground bitumen deposits. ## Mineral Associations This mineral co-occurs with other rare minerals typical of the Hatrurim Formation, such as larnite, brownmillerite, mayenite, gehlenite, rankinite, ye'elimite, as well as calcite and hematite. ## Localities The only confirmed occurrence of shulamite in the world is its type locality - the Hatrurim Formation, specifically an area in the Hatrurim Basin in Israel. The mineral has also been found in Jordan, in the Daba-Siwaqa area, which is a geological extension of the Hatrurim Formation.

Rarity

Very rare

For collectors

## Quality Criteria The quality of shulamite specimens is primarily assessed based on the richness and abundance of microcrystals on the rock matrix and their association with other rare minerals. Since the crystals are microscopic, their individual form is not the main criterion. Key factors are the certainty of analytical identification and accurate locality documentation. ## Popular Localities The most prized specimens come from the type locality in the Hatrurim Basin, Israel. This is the only source of material that enters the collector's market.

Care and storage

## Cleaning Shulamite specimens, due to their microscopic nature, usually do not require cleaning. If necessary, mechanical methods should be avoided. Compressed air (from a safe distance) can be used to remove dust. ## What to Avoid Contact with acids and other aggressive chemicals should be avoided. Despite its relatively high hardness, specimens are brittle and susceptible to mechanical damage due to the small size of the crystals. ## Storage Microscopic specimens should be stored in specialized "micromount" boxes that protect them from dust and mechanical damage. Vibrations and shocks should be avoided.

External references

Sources

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