Qeltite

Chemical formula: Ca₃Ti₄+Si₂(Fe₃+₂Si)O₁₄

Keltite is a rare mineral from the titanite group, discovered in Jordan, forming small, brown crystals in metamorphic rocks.

## Characteristics Keltite is a very rare silicate belonging to the titanite group. It typically occurs as small, individual, tabular or prismatic crystals, reaching up to 0.2 mm in size. It is a brittle mineral, brown to reddish-brown in color with a vitreous luster. ## Physical Properties Keltite is characterized by a Mohs hardness of 5. Its density is relatively high, approximately 3.72 g/cm³. This mineral is transparent to translucent. It exhibits weak pleochroism in shades of brown. ## Colors and Varieties The observed colors of keltite are brown and reddish-brown. No varieties have been distinguished. ## History and Name The mineral's name comes from the Qelt River in Palestine, flowing near its discovery site. It was first described by I.V. Galuskina and co-workers in 2013, and approved by the International Mineralogical Association (IMA) under number 2013-020. The type locality is the Hatrurim Formation in the Nabi Musa area of the Judean Desert. ## Uses Due to its extreme rarity and microscopic crystal sizes, keltite has no industrial applications. It is solely an object of scientific and collecting interest for specialized micromineral collectors.

Properties

Mohs hardness: 5
Luster: Vitreous
Streak: Light brown
Density: 3.72
Cleavage: None
Fracture: Uneven
Transparency: Transparent to translucent
Crystal system: Triclinic

Diagnostic features

## Identification Identification of keltite is possible almost exclusively using advanced analytical methods, such as Raman spectroscopy, electron microprobe (EDS/WDS), and X-ray diffraction (XRD). Visually, at the occurrence site, it can be suspected based on its brown color, vitreous luster, and co-occurrence with other rare minerals from the Hatrurim Formation. ## Distinguishing from Similar Minerals Keltite is very similar to other minerals from the titanite group, such as titanite and benitoite, as well as to members of the aenigmatite group. Definitive distinction from these minerals requires specialized laboratory analyses to determine the exact chemical composition and crystal structure. ## Crystal Forms Keltite forms small, tabular or short-prismatic crystals, often with a pseudohexagonal habit. The crystals are usually individual and well-formed, but their size does not exceed 0.2 mm.

Geological environment

## Genesis Keltite forms under conditions of high-temperature, low-pressure contact metamorphism (pyrometamorphism). It crystallizes in calc-silicate rocks that have undergone intense thermal alteration, characteristic of the Hatrurim Formation. ## Mineral Associations This mineral co-occurs with other rare minerals formed under similar conditions, such as larnite, brownmillerite, mayenite, jafsoanite, as well as with members of the garnet group (andradite) and melilite (gehlenite). ## Localities The only confirmed locality of keltite in the world is its type locality – the Hatrurim Formation in the Nabi Musa area of the Judean Desert, in the West Bank, Palestine.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of keltite specimens is primarily assessed based on the presence of well-formed, identifiable crystals. Due to their microscopic size, the abundance of occurrence on the rock matrix and contrast with surrounding minerals are crucial. Specimens with analytically confirmed crystal identity are most highly valued. ## Popular Localities The only source of keltite specimens is its type locality in the Hatrurim Formation in Palestine. Material from this locality is extremely rare on the collector's market.

Care and storage

## Cleaning Specimens containing keltite, due to the microscopic size of the crystals and their fragility, should be cleaned with utmost care. Only gentle dust removal using compressed air from a safe distance is recommended. Contact with water and any chemical agents should be avoided. ## What to Avoid Ultrasonic cleaners, strong water jets, acids, solvents, and sudden temperature changes should be absolutely avoided. The crystals are very small and brittle, making them easy to damage or lose. ## Storage Specimens should be stored in specialized "micromount" boxes, which protect them from dust, shocks, and mechanical damage. Store in stable conditions, away from moisture and direct sunlight.

Sources

IMA Mineral List (CNMNC)