Nanlingite

Chemical formula: NaCa<sub>5</sub>LiMg<sub>12</sub>(As<sup>3+</sup>O<sub>3</sub>)<sub>2</sub>[Fe<sup>2+</sup>(As<sup>3+</sup>O<sub>3</sub>)<sub>6</sub>]F<sub>14</sub>

Nanlingite is an extremely rare, complex arsenite of sodium, calcium, lithium, magnesium, and iron, found in the form of tiny, hexagonal crystals.

## Characteristics Nanlingite is an exceptionally rare mineral from the oxide group, specifically arsenites. It occurs as very small, hexagonal, tabular crystals, reaching up to 0.3 mm in size. It typically forms aggregates or appears as single, dispersed crystals within the host rock. It is transparent and has a vitreous luster. ## Physical Properties Nanlingite crystals are too small to precisely determine their hardness or density mechanically. The density has been calculated based on the chemical formula and unit cell parameters, and is approximately 3.89 g/cm³. The mineral exhibits perfect cleavage in one plane. ## Colors and Varieties Nanlingite is colorless. No colored or commercial varieties are known. ## History and Name The mineral's name comes from its discovery location – the Nanling Mountains in China. It was first described and approved as a new mineral by the International Mineralogical Association (IMA) in 2012 (IMA2012-089). The discovery was made in the Xianghualing tin deposit in Hunan Province. ## Applications Due to its extreme rarity and microscopic crystal size, nanlingite has no industrial applications. It is solely of scientific interest and is sought after by specialized collectors of rare minerals.

Properties

Luster
Vitreous
Streak
White
Density
3.89
Cleavage
Perfect on {0001}
Transparency
Transparent
Crystal system
Hexagonal

Diagnostic features

## Identification Identification of nanlingite is impossible without advanced analytical methods. This requires the use of energy-dispersive spectroscopy (EDS/EDX) or electron microprobe analysis (EMPA) to confirm its unique chemical composition. Visually, it can be located under a microscope as tiny, colorless, hexagonal plates. ## Distinguishing from Similar Minerals Due to its microscopic nature, visual differentiation from other co-occurring colorless minerals (e.g., quartz, fluorite) is practically impossible. The only reliable method is chemical analysis. ## Crystal Forms Nanlingite crystallizes in hexagonal, tabular, or platy forms. They are usually very thin and flat, with a hexagonal outline.

Geological environment

## Genesis Nanlingite forms in altered (greisenized) granites. It is a hydrothermal mineral, crystallizing in the late stage of magmatic evolution, in an environment rich in lithium, fluorine, and arsenic. ## Mineral Associations This mineral co-occurs with other minerals typical of greisenized granites, such as quartz, fluorite, muscovite, protolithionite, topaz, cassiterite, arsenopyrite, and other rare minerals, including those from the apatite group. ## Localities The only confirmed locality of nanlingite in the world is its type locality – the Xianghualing polymetallic tin deposit, in Linwu County, Chenzhou Prefecture, Hunan Province, China.

Rarity

Extremely rare

For collectors

## Quality Criteria The quality of a nanlingite specimen primarily depends on the richness and quantity of crystals on the rock matrix, as well as their size, although even the largest do not exceed a fraction of a millimeter. Specimens with well-formed, undamaged crystals visible under a microscope are highly valued. The aesthetics of the host rock and the presence of associated minerals are also important. ## Popular Localities The only source of nanlingite specimens is the Xianghualing mine in China. All specimens available on the collector's market originate from this single locality.

Care and storage

## Cleaning Specimens containing nanlingite should generally not be cleaned mechanically or chemically due to the microscopic size and delicacy of the crystals. If absolutely necessary, compressed air (from a safe distance) can be used to remove loose dust. ## What to Avoid Avoid contact with all chemicals, acids, and detergents. Do not subject it to ultrasonic cleaning. Due to the presence of arsenic, avoid inhaling dust and wash hands after handling the mineral. ## Storage Specimens should be stored in stable conditions, away from moisture and extreme temperatures. The safest method is to keep them in closed, padded "micromount" boxes, which protect delicate crystals from mechanical damage and dust.

Sources

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