Noonkanbahite

Chemical formula: KNaBaTi<sup>4+</sup><sub>2</sub>(Si<sub>4</sub>O<sub>12</sub>)O<sub>2</sub>

Noonkanbahite is a very rare mineral from the cyclosilicate group, found in lamproites, distinguished by its complex chemical composition.

## Characteristics Noonkanbahite is an extremely rare titanium-silicate mineral, belonging to the titanosilicate group with a structure similar to batisite. It occurs as very small, prismatic crystals, usually less than 1 mm in size, embedded in other minerals. Its crystals are elongated and often have a bladed or acicular habit. Due to its size and mode of occurrence, it is a mineral primarily accessible to advanced micromounters and scientific institutions. ## Physical Properties Noonkanbahite crystals exhibit a luster described as vitreous to resinous. The mineral is brittle and has a hardness of approximately 6 on the Mohs scale. Its density, calculated based on the chemical formula and unit cell parameters, is about 3.75 g/cm³. ## Colors and Varieties Noonkanbahite has a characteristic, deep reddish-brown color. It is translucent to almost opaque. No varieties have been distinguished. ## History and Name The mineral was first described in 1985 by A. L. Bishop, I. C. Fitzgerald, G. M. K. Lawrance, and A. J. Criddle. Its name comes from its discovery locality – the Noonkanbah sheep station in the Kimberley region of Western Australia, where the Wolgidee Hills lamproite intrusion, its type locality, is situated. ## Uses Noonkanbahite has no industrial applications. Its significance is purely scientific and as a collector's item, as a unique member of the titanosilicate group.

Properties

Mohs hardness
6
Luster
Vitreous to Resinous
Streak
Pale brown
Density
3.75
Cleavage
Good on {100} and {210}
Fracture
Uneven
Transparency
Translucent to Opaque
Crystal system
Orthorhombic

Diagnostic features

## Identification Identification of noonkanbahite is possible only through advanced laboratory methods, such as EDS/WDS (energy-dispersive/wavelength-dispersive spectroscopy) analysis to confirm its unique chemical composition (presence of potassium, sodium, barium, titanium, and silicon) and X-ray diffraction. Visually, on a micro scale, it can be suspected based on its reddish-brown color and prismatic habit within lamproites from Wolgidee Hills. ## Differentiation from Similar Minerals It can be confused with other rare titanosilicates found in the same environment, such as priderite or jeppeite. Priderite has a similar color but crystallizes in the tetragonal system. Jeppeite also has a similar composition but a different structure. Definitive differentiation requires chemical and structural analysis. ## Crystal Forms Noonkanbahite forms small, prismatic crystals, elongated along one of the crystallographic axes. They usually occur as single, isolated crystals or small aggregates embedded in other minerals of the host rock.

Geological environment

## Genesis Noonkanbahite is an igneous mineral, crystallizing as a late phase in potassium- and titanium-rich, silica-undersaturated volcanic rocks, specifically lamproites. It forms under conditions of high temperature and specific magma chemistry. ## Mineral Associations This mineral co-occurs with other rare minerals typical of lamproites from Wolgidee Hills. Its most important associations include priderite, jeppeite, wadeite, shcherbakovite, richterite, perrierite, and volcanic glass. ## Localities The only confirmed locality for noonkanbahite in the world is its type locality – the Wolgidee Hills lamproite intrusion, located near Fitzroy Crossing in the Kimberley region of Western Australia.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of noonkanbahite specimens is primarily judged by the size and development of the crystals, which is a rarity. The most desirable specimens are those with clearly visible, sharply terminated prismatic crystals, even if they are fractions of a millimeter. Contrast with surrounding minerals (matrix) also enhances aesthetic value. The purity and intensity of the reddish-brown color are secondary characteristics. ## Popular Localities The only source of noonkanbahite specimens is its type locality in Wolgidee Hills, Western Australia. All specimens available on the collector's market originate from this single location.

Care and storage

## Cleaning Due to the extreme rarity and small size of the crystals, specimens containing noonkanbahite (usually micromounts) should not be cleaned mechanically or chemically. Any contaminants, such as dust, should be removed only with a photographic blower bulb or compressed air from a safe distance. ## What to Avoid Avoid contact with any chemicals, including acids and bases. Do not use ultrasonic cleaners. Specimens must not be heated or exposed to sudden temperature changes. Protect them from direct, prolonged exposure to sunlight. ## Storage Specimens containing noonkanbahite should be stored in specialized micromount boxes that protect them from dust, moisture, and mechanical damage. Store in stable room conditions, away from sources of vibration and light.

Sources

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