Haitaite-(La)

Chemical formula: LaU4+Fe3+2(Ti4+13Fe2+4Fe3+)O38

Haitaiite-(La) is an extremely rare, black mineral with a submetallic luster, which is a complex oxide of titanium, lanthanum, uranium, and iron.

Description

## Characteristics Haitaiite-(La) is a mineral from the crichtonite group, occurring as irregular, anhedral grains up to 1x2 cm in size, embedded in the rock. It is completely opaque, black in color, and has a submetallic luster. Its surface can be dull or covered with weathering products. Due to its uranium content, it is a radioactive mineral. ## Physical Properties The Mohs hardness of haitaiite-(La) is 5.5-6. The mineral is characterized by a density of 4.86 g/cm³, which is a relatively high value, typical for minerals containing heavy elements. It does not exhibit cleavage, and its fracture is conchoidal. It is brittle. ## Colors and Varieties This mineral is monochromatic – it occurs exclusively in black. No colored or commercial varieties are known. ## History and Name It was first described in 1995 by Ma Zhesheng and other researchers. Its name comes from the discovery locality – the Haita pegmatite field in Weishan County, China. The "-(La)" suffix in the name indicates that lanthanum is the dominant rare earth element in its structure, distinguishing it from other potential minerals in this series. ## Uses Haitaiite-(La) has no industrial applications. It is solely an object of scientific interest and is valued by specialized collectors of rare minerals.

Diagnostic features

## Identification Key diagnostic features include black color, submetallic luster, conchoidal fracture, and lack of cleavage. The most important indicator, however, is strong radioactivity, which can be detected with a Geiger counter. High density is also a helpful characteristic. ## Distinguishing from Similar Minerals Haitaiite-(La) can be confused with other black, radioactive pegmatite minerals, such as euxenite, samarskite, davidite, or aeschynite. All have a similar appearance and often occur in the same environment. Positive identification is almost exclusively possible using advanced analytical methods, such as X-ray microanalysis (EDS/WDS), which allows for the determination of chemical composition and confirmation of the dominance of lanthanum, uranium, titanium, and iron. ## Crystal Forms This mineral does not form well-developed crystals. It occurs as irregular, anhedral grains and aggregates, embedded in other minerals of the host rock.

Geological environment

## Genesis Haitaiite-(La) is a magmatic mineral, crystallizing in the late stages from residual melts in syenitic pegmatites. Its formation is associated with a high concentration of rare earth elements (mainly lanthanum), titanium, uranium, and iron. ## Mineral Associations This mineral occurs in association with other minerals typical of syenitic pegmatites. It most commonly co-occurs with aegirine, microcline, zircon, and minerals from the crichtonite group (to which it belongs), such as davidite. ## Localities The only confirmed locality of haitaiite-(La) in the world is its type locality – the Haita pegmatite field, in Weishan County, Jining Prefecture, Shandong Province, China.

Rarity

Extremely rare

Collector aspects

## Quality Criteria The quality of a haitaiite-(La) specimen is primarily assessed based on the size and distinctness of the grain or mineral aggregate against the host rock (matrix). Since it is an extremely rare mineral and occurs in an embedded form, any visible specimen has collector's value. Specimens with clear associations with other rare minerals are particularly prized. ## Popular Localities All collector specimens come from a single location in the world – the Haita pegmatite field in China. This is the only source of this mineral.

Care and storage

## Cleaning Due to radioactivity and brittleness, cleaning should be kept to a minimum. It is recommended to remove dust with a soft brush or compressed air from a safe distance. Wet cleaning should be avoided to prevent the spread of potentially radioactive particles. ## What to Avoid The mineral is radioactive – avoid inhaling dust and direct, prolonged skin contact. It must not be cut, ground, or mechanically processed outside of a specialized laboratory. Avoid contact with acids and other chemicals. It should not be cleaned in ultrasonic cleaners. ## Storage Haitaiite-(La) specimens must be stored in tightly sealed, lead or glass containers with a clear warning label about radioactivity. They should be kept away from areas of permanent human habitation and from other minerals that may be sensitive to radiation (e.g., smoky quartz, some fluorites).