Nabimusaite

Chemical formula: KCa₁₂(SiO₄)₄(S⁶⁺O₄)₂O₂F

Nabimusaite is a rare mineral from the arctite group, a colorless potassium calcium fluorosulfate silicate, discovered in Palestine.

## Characteristics Nabimusaite is a very rare mineral belonging to the arctite group. It forms small, colorless crystals, which usually occur as aggregates. It is transparent and characterized by a vitreous luster. Due to its extremely rare occurrence and small crystal sizes, it is a mineral known mainly in scientific and specialized circles. ## Physical Properties This mineral has a hardness of 5 on the Mohs scale, making it relatively hard. Its density is approximately 3.12 g/cm³. It exhibits imperfect cleavage in one plane. The luster is typically vitreous. ## Colors and Varieties Nabimusaite is naturally colorless. No colored varieties or trade names are known. ## History and Name The mineral's name comes from its discovery locality, Nabi Musa (Arabic for "Prophet Moses"), which is near the type locality. It was first described and recognized as a new mineral species by the International Mineralogical Association (IMA) in 2011. The discovery was made in the Jebel Harmun area in Palestine. ## Uses Nabimusaite has no practical industrial applications. Its significance is purely scientific and collectible, as a unique and rare mineralogical species.

Properties

Mohs hardness: 5
Luster: Vitreous
Streak: White
Density: 3.119
Cleavage: imperfect along (001).
Transparency: Transparent
Crystal system: Trigonal

Diagnostic features

## Identification Identification of nabimusaite is based on its physical and chemical properties, which, however, can only be examined under laboratory conditions (EDS, XRD analysis). Under collecting conditions, identification is practically impossible without advanced equipment. Key is the association with the type locality and co-occurring minerals. ## Distinguishing from Similar Minerals It can be confused with other colorless minerals occurring in the same environment, such as calcite or other rare silicates. Differentiation requires specialized studies, as visual characteristics are not sufficiently distinctive. ## Crystal Forms Nabimusaite forms tabular or platy crystals, often gathered in rosette-like or spherical aggregates. Crystals are usually small, not exceeding a few millimeters.

Geological environment

## Genesis Nabimusaite forms as a result of natural combustion of sedimentary rocks (Hatrurim Formation), under conditions of contact pyrometamorphism. This is a process occurring at high temperature and low pressure, where bitumen-rich rocks ignite. ## Mineral Associations This mineral co-occurs with other rare minerals formed under similar conditions, such as larnite, brownmillerite, mayenite, ye'elimite, as well as calcite and ettringite. ## Localities The only confirmed occurrence of nabimusaite in the world is its type locality: Jebel Harmun in Quds Governorate, West Bank, Palestine. This is part of the unique geological Hatrurim Formation, also known as the "Mottled Zone Complex."

Rarity

Extremely rare

For collectors

## Quality Criteria Due to its extreme rarity, every authentic nabimusaite specimen is valuable. Specimens with well-formed, even if small, crystals, clearly visible on the rock matrix, are most highly valued. Association with other rare minerals from this locality is also important. ## Popular Localities The only source of specimens is the type locality in Palestine. Material from this location is extremely difficult to obtain and rarely appears on the collector's market.

Care and storage

## Cleaning Due to the rarity and delicacy of the specimen, cleaning should be kept to an absolute minimum. If necessary, a soft brush can be used to remove dust. Avoid water and any chemical agents. ## What to Avoid Avoid contact with water, acids, detergents, and ultrasound. The mineral should be protected from sudden temperature changes and direct, prolonged exposure to sunlight. Due to its cleavage, impacts and pressure should be avoided. ## Storage Nabimusaite specimens should be stored in stable conditions, preferably in a closed display box, away from dust, moisture, and light. Each specimen should be isolated from other minerals to prevent scratches and mechanical damage.